As filed with the Securities and Exchange Commission on October 23, 2002

Registration Nos. 333-99019
333-99019-01

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

AMENDMENT NO. 3

TO

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Addresses, including zip code, and telephone numbers, including area code, of registrants' principal executive offices)

CT Corporation System
1633 Broadway, 30th Floor
New York, New York 10019
(800) 624-0909
(Name, address, including zip code, and telephone number, including area code, of registrants' agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public:
As soon as practicable after the effective date of this registration statement.

        If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 of the Securities Act of 1933, check the following box. / /

        If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. / /

        If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. / /

        If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. / /

        If the delivery of the prospectus is expected to be made pursuant to Rule 434 under the Securities Act, check the following box. / /

        The registrants hereby amend this registration statement on such date or dates as may be necessary to delay its effective date until the registrants shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, or until this registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

Subject to Completion. Dated October 23, 2002.

The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

5,000,000 Units

Platinum Underwriters Holdings, Ltd.

Equity Security Units

        This is an offering of equity security units of Platinum Underwriters Holdings, Ltd. Each equity security unit has a stated amount of $25 and will initially consist of (a) a contract pursuant to which you agree to purchase, for $25, Common Shares of Platinum Holdings on                    , 2005 and (b) a 1/40, or 2.5%, ownership interest in a senior note of its subsidiary, Platinum Underwriters Finance, Inc., with a principal amount of $1,000. The ownership interest in the senior note will initially be held as a component of your unit and be pledged to secure your obligation to purchase Common Shares of Platinum Holdings under the related purchase contract. The senior notes will be guaranteed by Platinum Holdings on a senior, unsecured basis.

        Platinum Holdings will make quarterly contract adjustment payments to you under the purchase contract at the annual rate of        % of the stated amount of $25 per purchase contract. In addition, Platinum Finance will make quarterly interest payments on the senior notes at the initial annual rate of        %. Platinum Holdings has the right to defer the contract adjustment payments on the purchase contracts, but Platinum Finance does not have the right to defer the interest payments on the senior notes. The interest rate on the senior notes will be reset, and the senior notes remarketed. The senior notes are unsecured and rank equally with all of Platinum Finance's other unsecured senior indebtedness. The units will be sold initially by the underwriters in a minimum number of 40 units.

        Prior to this offering and the concurrent initial public offering of Common Shares of Platinum Holdings, there has been no public market for the units or Platinum Holdings' Common Shares.

        In addition to offering these units, Platinum Holdings is concurrently offering 30,040,000 of its Common Shares, plus up to an additional 4,506,000 Common Shares if the underwriters for that offering exercise their option to purchase additional Common Shares. The completion of this offering of equity security units is subject to the completion of the initial public offering of Common Shares of Platinum Holdings.

        The normal units and the Common Shares that will be issued in the concurrent initial public offering have been approved for listing on the New York Stock Exchange, subject to notice of issuance, under the symbols "PTP Pr M" and "PTP", respectively.

        Immediately after this offering, public shareholders, The St. Paul Companies, Inc. and RenaissanceRe Holdings Ltd. will own 75.1%, 15.0% and 9.9% of the outstanding Common Shares, respectively, assuming no exercise by the underwriters, St. Paul or RenaissanceRe of their options to purchase additional Common Shares in connection with the concurrent initial public offering.

        See "Risk Factors" beginning on page 31 to read about certain factors you should consider before buying units.

        Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

        The initial public offering price set forth above does not include accumulated contract adjustment payments and accrued interest, if any. Contract adjustment payments on the purchase contracts and interest on the senior notes will accrue from the date of original issuance of the units, expected to be                          , 2002.

        To the extent that the underwriters sell more than 5,000,000 units, the underwriters have the option to purchase, not later than 13 days after the initial issuance of the units, up to an additional 750,000 units from Platinum Holdings at the initial public offering price less the underwriting discount.

        The underwriters expect to deliver the units against payment in New York, New York on                          , 2002.

Prospectus dated                            , 2002.

PROSPECTUS SUMMARY

        Platinum Underwriters Holdings, Ltd. is a newly formed company that will conduct its business through three operating subsidiaries, Platinum Underwriters Reinsurance, Inc. ("Platinum US"), Platinum Re (UK) Limited ("Platinum UK") and Platinum Underwriters Bermuda, Ltd. ("Platinum Bermuda"). Platinum UK and Platinum Bermuda are newly formed companies, while Platinum US has been in existence since 1995 and is an inactive, wholly owned subsidiary of The St. Paul Companies, Inc. Platinum UK is, and upon completion of this offering, Platinum US will be, owned through Platinum Regency Holdings ("Platinum Ireland"), a newly formed and wholly owned intermediate Irish holding subsidiary of Platinum Underwriters Holdings, Ltd. Platinum US will be owned directly by Platinum Underwriters Finance, Inc. ("Platinum Finance"), a newly formed Delaware corporation, which, upon completion of this offering, will be a wholly owned subsidiary of Platinum Ireland.

        The "Company", "Platinum", "we", "us" and "our" refer to Platinum Underwriters Holdings, Ltd.'s consolidated operations, including Platinum US, unless the context otherwise indicates. "Platinum Holdings" refers solely to Platinum Underwriters Holdings, Ltd. Concurrent with the completion of this offering, St. Paul will contribute to Platinum between $121 million and $126 million in cash, which we refer to as the "Cash Contribution." The St. Paul Companies and its subsidiaries will also contribute to Platinum substantially all of their continuing reinsurance business and related assets, including all of the outstanding capital stock of Platinum US, referred to herein as the "Transferred Business," having a net tangible book value of approximately $11 million as of June 30, 2002 (after reflecting a dividend of $15 million to be paid, prior to the completion of the Equity Public Offering, to United States Fidelity and Guaranty Company, the current parent of Platinum US). Reinsurance is an arrangement in which a reinsurance company indemnifies an insurer or other reinsurer, which is referred to as a "ceding company" or "cedent", against all or a portion of the insurance or reinsurance risks underwritten by the ceding company under one or more policies. "St. Paul" refers to The St. Paul Companies, Inc., which is sponsoring our formation, and, unless the context otherwise requires, its subsidiaries. "St. Paul Re" refers to the reinsurance segment of St. Paul prior to this offering, which includes the continuing business and related assets being transferred to Platinum upon completion of this offering as well as the reinsurance business that will remain with St. Paul after this offering and not be renewed and will thereafter expire when claims are ultimately resolved, which is referred to as the "run-off."

        We intend to commence our property and casualty reinsurance business operations, whereby we indemnify insurers and other reinsurers against all or a portion of their insurance or reinsurance risks for property loss and related damage and negligence resulting in bodily injury or property damage, upon completion of this offering of equity security units, which we refer to as the "ESU Offering." Concurrently with this offering, we will offer 30,040,000 Common Shares by means of a separate prospectus, plus up to an additional 4,506,000 Common Shares if the underwriters' option to purchase additional Common Shares is exercised in full. We refer to this offering as the "Equity Public Offering." The closing of each offering is conditioned on the concurrent closing of the other offering.

        Concurrently with the completion of the Equity Public Offering, St. Paul will make the Cash Contribution and contribute the Transferred Business to us in exchange for our issuance to St. Paul, on a private placement basis, of 6,000,000 Common Shares and a ten-year option, referred to as the "St. Paul Option", which will entitle St. Paul to buy from us up to 6,000,000 additional Common Shares at a price per share equal to 120% of the initial public offering price. St. Paul will own 15.0% of Platinum Holdings' outstanding Common Shares following the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment (each as defined below), which Common Shares will be limited to 9.9% of the voting power of the outstanding Common Shares. If the underwriters exercise their option to purchase additional Common Shares in the Equity Public Offering, St. Paul

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has the option to purchase, at a price per share equal to the initial public offering price, less the underwriting discount, as many additional Common Shares as are required in order for it to retain its 15.0% interest (a maximum of 900,000 additional Common Shares). In this prospectus, we refer to our issuance to St. Paul of the 15.0% interest in our Common Shares and the St. Paul Option in exchange for the Cash Contribution and the Transferred Business as the "St. Paul Investment."

        Also, concurrently with the completion of the Equity Public Offering, RenaissanceRe Holdings Ltd. (including its subsidiaries, unless the context otherwise requires "RenaissanceRe"), a Bermuda company that provides reinsurance and insurance coverage, will purchase from us in a private placement, at a price per share equal to the initial public offering price, less the underwriting discount, 3,960,000 Common Shares, or 9.9% of the Common Shares outstanding upon completion of the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment (as defined below). If the underwriters exercise their option to purchase additional Common Shares in the Equity Public Offering, RenaissanceRe has the option to purchase, at a price per share equal to the initial public offering price, less the underwriting discount, as many additional Common Shares as are required in order for it to retain its 9.9% interest (a maximum of 594,000 Common Shares). As additional consideration, RenaissanceRe will receive a ten-year option, referred to as the "RenaissanceRe Option", to purchase up to an additional 2,500,000 Common Shares at a price per share equal to 120% of the initial public offering price. In this prospectus, we refer to this private placement as the "RenaissanceRe Investment." The closing of this private placement to RenaissanceRe is conditioned on the completion of the Equity Public Offering, the ESU Offering and the St. Paul Investment.

        We will have a total capitalization of between approximately $955 million (assuming an initial public offering price of $22.00 per Common Share, a Cash Contribution of $121 million and no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares or the underwriters' option to purchase additional equity security units) and approximately $1,142 million (assuming an initial public offering price of $23.00 per Common Share, a Cash Contribution of $126 million and full exercise of the underwriters', St. Paul's and RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering and the underwriters' option to purchase additional equity security units), upon completion of the Equity Public Offering, the ESU Offering, the St. Paul Investment and the RenaissanceRe Investment. The determination of the amount of the Cash Contribution will be made when the terms of the Equity Public Offering are finally determined. The pro forma net tangible book value per Common Share following the Equity Public Offering, the ESU Offering, the St. Paul Investment and the RenaissanceRe Investment will be $21.24 per share based on an assumed initial public offering price of $22.50 per Common Share (the mid-point of the range at which Platinum Holdings proposes to offer the Common Shares) and a Cash Contribution of $123 million (the mid-point of the $121 million to $126 million range of the Cash Contribution), assuming no exercise of the underwriters' options to purchase additional Common Shares or the underwriters' option to purchase additional equity security units and without giving effect to the settlement of the purchase contracts included in the equity security units.

        In this prospectus, amounts are expressed in U.S. dollars and the financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP"), except as otherwise indicated.

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The Company

General

        Our objective is to provide property and casualty reinsurance coverages to a diverse clientele of insurers and select reinsurers on a worldwide basis. We will operate principally by using reinsurance brokers to market our products and principally as a lead reinsurer on treaty reinsurance business. In treaty reinsurance, a reinsurer accepts a specified portion of a category of risks insured by a ceding insurer or reinsurer. A substantial majority of our business will be written as excess-of-loss reinsurance, which indemnifies the reinsured against all or a specified portion of loss above a specified amount. We intend to organize our worldwide reinsurance business around three operating segments:

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Global Property and Marine. The Global Property and Marine operating segment will include principally property reinsurance coverages and marine reinsurance coverages. Marine reinsurance coverages include all types of marine vessels and related warehouses and liabilities. We intend to focus our underwriting activities primarily on catastrophe excess-of-loss and per risk excess-of-loss contracts. Catastrophes are events such as hurricanes and earthquakes that produce pre-tax losses before reinsurance which, in our definition, are in excess of $10 million to us or $1 billion to the insurance industry, and per risk excess-of-loss contracts cover losses in excess of a specified level on a single risk, rather than aggregate losses for all covered risks. We intend to write other types of property reinsurance as well, including selected property proportional reinsurance, where we will share a proportional part of the original premiums and losses of the reinsured. This segment generated $315 million, or 22.8%, of Platinum's 2001 pro forma net premiums written, which are gross written premiums less premiums ceded to reinsurers.



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Global Casualty. The Global Casualty operating segment will include principally general and automobile liability, professional liability, workers' compensation, accident and health coverages and casualty clash (casualty clash covers losses arising from a single set of circumstances covered by more than one cedent's insurance policy or multiple claimants on one policy). We intend to focus our underwriting activities primarily on excess-of-loss reinsurance coverages. This segment generated $592 million, or 42.8%, of Platinum's 2001 pro forma net premiums written.



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Finite Risk. The Finite Risk operating segment, which writes policies under which our aggregate risk and return are generally capped at a finite amount, will include principally non-traditional reinsurance treaties, including multi-year excess-of-loss (in which the cedent funds the agreed level of loss activity over a multi-year period, and the reinsurer charges an additional amount to provide a profit margin and to cover its costs and the risk that losses are worse than the agreed level), aggregate stop loss (which provides protection from losses arising from a wide range of circumstances in excess of an aggregate specified level), finite quota share (in which the reinsurer's losses and profit potential are capped at specified amounts), loss portfolio transfer (which typically transfers to the reinsurer all liabilities for incurred losses, subject to an aggregate loss limit specified in the contract), and adverse loss development contracts (which typically provide reinsurance coverage for losses in excess of the carried loss reserves of the ceding company at the transaction date). We intend to provide clients, either directly or through brokers, with customized solutions for their risk management and other financial management needs. We intend to focus our finite risk underwriting activities primarily on multi-year excess-of-loss and aggregate stop loss reinsurance treaties. Coverage classes within these products will primarily include property, casualty and marine exposures. This segment generated $475 million, or 34.4%, of Platinum's 2001 pro forma net premiums written.

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        In addition, we may write other property and casualty reinsurance on an opportunistic basis. For a discussion of the basis on which pro forma net premiums written were determined, see
"—Selected Pro Forma Financial Information and Operating Data" below.

Background and the Transferred Business

        St. Paul and its subsidiaries constitute one of the oldest insurance organizations in the United States, dating back to 1853. Through its division St. Paul Re, St. Paul has been engaged in the reinsurance business since 1983. In December of 2001, in an effort to enhance the profitability of its reinsurance business, St. Paul decided to narrow the product focus of its reinsurance operations and to exit certain lines of that business. As part of this effort, St. Paul Re reduced its anticipated 2002 exposure and expenses by exiting unprofitable lines of business and reducing the number of reinsurance branch offices outside the United States. The narrowing of reinsurance product lines included exiting aviation, bond and credit reinsurance coverages, as well as certain financial risk and capital markets lines. International branch office closings included Munich, Brussels, Hong Kong, Sydney and Singapore. In addition to curtailing various reinsurance operations, St. Paul's management decided that its reinsurance business and its primary insurance business should ideally operate as separate entities because of their different risk profiles and business characteristics.

        Accordingly, St. Paul determined to sponsor the formation of Platinum Holdings and its subsidiaries. Contingent upon the completion of the Equity Public Offering, St. Paul will contribute to us the Cash Contribution and the Transferred Business through the arrangements described below:

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Cash Contribution. At the completion of the Equity Public Offering, St. Paul will make the Cash Contribution in the amount of between $121 million and $126 million. The determination of the amount of the Cash Contribution will be made when the terms of the Equity Public Offering are finally determined. An assumed Cash Contribution of $123 million will result in a pro forma net tangible book value per Common Share of $21.24 following the Equity Public Offering, the ESU Offering, the St. Paul Investment and the RenaissanceRe Investment based on an assumed initial public offering price of $22.50 per Common Share (the midpoint of the range at which Platinum Holdings proposes to offer the Common Shares) and assuming no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering or the underwriters' option to purchase additional equity security units. Cash Contributions of $121 million and $126 million will result in net tangible book values of $20.76 and $21.71 per Common Share, respectively, assuming an initial public offering price of $22.00 and $23.00, respectively, and no exercise of the underwriters' options to purchase additional Common Shares or additional equity security units and without giving effect to the settlement of the purchase contracts included in the equity security units.



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Renewal Opportunities and Commitments. We will be acquiring from St. Paul Re its existing customer lists and the right to seek to renew substantially all of St. Paul Re's continuing reinsurance contracts. We also will assume commitments, if any, of St. Paul Re to offer reinsurance coverages in the future.



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Assumed Reinsurance Contracts. Through 100% quota share retrocession agreements (the "Quota Share Retrocession Agreements"), we will reinsure substantially all of the reinsurance contracts entered into by St. Paul Re on or after January 1, 2002, which we refer to as the "Assumed Reinsurance Contracts". St. Paul Re will retain all of its reinsurance exposure not being transferred to us and will administer the associated run-off. Consequently, we will not assume any underwriting exposure with respect to reinsurance contracts entered into by

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St. Paul prior to January 1, 2002, except as noted below with respect to finite reinsurance. St. Paul will also retain all liabilities relating to the flooding in Europe in August 2002 and an intermediate layer of liability for named storms (which are any tropical cyclones assigned a name by the National Hurricane Center) in existence at the time of completion of the Equity Public Offering which cause insured damage within ten days of such time, as described herein. We will receive as consideration cash and other assets in an amount equal to the aggregate of all applicable loss reserves (excluding reserves relating to liabilities retained by St. Paul), allocated loss adjustment expense reserves (which are reserves relating to the expense incurred in settling claims), other reserves related to non-traditional reinsurance treaties, ceding commission reserves (which are reserves relating to commissions payable to ceding insurers) and unearned premium reserves (which are reserves equal to the difference between premiums written and premiums earned) subject to agreed upon adjustments, net of ceding commissions under the Quota Share Retrocession Agreements as of the transfer date (which is 12:01 a.m. on the day immediately following the date of the completion of the Equity Public Offering). Underwriting gain or loss with respect to the Assumed Reinsurance Contracts for the period from January 1, 2002 to the transfer date will be retained by St. Paul.

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The terms of the Quota Share Retrocession Agreements provide, with limited exceptions, that retrocessional reinsurance, which is reinsurance obtained by a reinsurer to insure against all or a portion of its reinsurance written, purchased by St. Paul Re shall be for our expense and shall inure to our benefit in respect of the Assumed Reinsurance Contracts, providing us with remaining retrocessional reinsurance coverage for such contracts through 2002 or the earlier termination or expiration of the various retrocession agreements. We will bear all the risk associated with non-payment by third-party retrocessionaires under such retrocessional reinsurance. All the Quota Share Retrocession Agreements will take effect as of 12:01 a.m. on the day immediately following the date of the completion of the Equity Public Offering. Accordingly, while St. Paul will be contractually committed to effect the transfer, the effective time of the transfer of the Assumed Reinsurance Contracts will occur after the sale to investors of Common Shares in the Equity Public Offering.



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In the case of business written in the United States and the United Kingdom, we will have the right to underwrite specified reinsurance business on behalf of St. Paul for a period of one year following the completion of the Equity Public Offering in cases where we are unable to underwrite that business ourselves because, despite using our reasonable best efforts, we have not obtained the necessary regulatory license or approval to do so or we have not yet been approved as a reinsurer by the cedent, and we will reinsure such business pursuant to the Quota Share Retrocession Agreements or, following receipt by Platinum UK of a license from the Financial Services Authority (the "FSA"), may reinsure all or a part of such business pursuant to a quota share retrocession agreement to be entered into between Platinum UK and St. Paul Re UK. This will allow us to participate in reinsurance business which is bound after the completion of the Equity Public Offering without any delay occasioned by the start-up of our operations, including the lack of required licenses, and facilitate the transition of St. Paul Re's business to us.



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For a period of three years following the completion of the Equity Public Offering, we will underwrite on behalf of St. Paul, with the consent of St. Paul, renewals of in-force contracts of finite reinsurance. St. Paul will retrocede to us 100% of the unpaid and future losses under currently in-force contracts, and we will have the option to reinsure losses under certain renewed contracts and will be required to offer to reinsure losses

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under other renewed contracts, for a fair market retrocession premium pursuant to the Quota Share Retrocession Agreements. Under the Quota Share Retrocession Agreements, a portion of future premiums will be applied to settle balances related to prior year experience for the benefit of St. Paul. St. Paul will have an option to renew this arrangement with us for a subsequent period of two years. In the United Kingdom, this arrangement will be limited to finite treaties which St. Paul Re has entered into with a small number of identified cedents and any further finite treaties which may be entered into on behalf of St. Paul Re UK prior to the first anniversary of the completion of the Equity Public Offering.

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Related Assets. We will be acquiring from St. Paul tangible and intangible assets relating to the continuing businesses being transferred to us, including furniture and equipment, systems and software, assignments of leases, licenses and other assets, as well as all of the outstanding capital stock of Platinum US.



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Employees. Upon or following the completion of the Equity Public Offering, we expect to employ approximately 150 employees previously employed by St. Paul Re.

        St. Paul has agreed with us that, subject to certain exceptions, for a period of two years following the completion of the Equity Public Offering, it will not offer reinsurance of the type covered by the Assumed Reinsurance Contracts and for which we have acquired renewal rights or hire certain of our employees.

        For a discussion of the share ownership interests St. Paul will obtain for its contribution of the Transferred Business, see "—St. Paul's Share Ownership" below.

Our Organization

        The following chart summarizes our corporate structure upon completion of the transactions contemplated by this prospectus. Our operating business will be conducted by Platinum US, Platinum UK and Platinum Bermuda. Platinum Bermuda expects to reinsure up to approximately 70% of Platinum US's reinsurance business, excluding business subject to the Quota Share Retrocession Agreements, written after the completion of the Equity Public Offering, and we are seeking consent from the FSA for Platinum Bermuda to reinsure up to approximately 55% of Platinum UK's reinsurance business, excluding business subject to the Quota Share Retrocession Agreements, written after the Equity Public Offering; however, such consent may not be granted. St. Paul will continue to write reinsurance in the United Kingdom and reinsure it 100% to us for up to one year following the completion of the Equity Public Offering. For a discussion of potential future limits on the portion of the reinsurance written by Platinum UK after the completion of the Equity Public Offering which can be reinsured to Platinum Bermuda, see "Business—Our Business—Regulation—U.K. Regulation—Proposed Limits on Concentration of Reinsurance Exposures."

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Management and Directors

        We have assembled a senior management team of experienced insurance industry professionals, whose backgrounds include underwriting and marketing property and casualty reinsurance worldwide. Steven H. Newman, who is the Chairman of Platinum Holdings' Board of Directors, Jerome T. Fadden, who is Platinum Holdings' President and Chief Executive Officer, William A. Robbie, who is Chief Financial Officer of Platinum Holdings, Michael E. Lombardozzi, who is General Counsel of Platinum Holdings, Michael D. Price, who will be President and Chief Underwriting Officer of Platinum US, and Neal J. Schmidt, who will be Chief Actuary of Platinum US, in each case upon completion of the Equity Public Offering, have extensive experience in the global property and casualty reinsurance industry. The new senior management team intends to initiate a number of actions to improve the underwriting performance and profitability of the Company. These actions are described more fully under "—Platinum's Strategy" below.

        Our Board of Directors consists of seven members: Mr. Newman; Mr. Fadden; Jay S. Fishman, Chairman of the Board of Directors and Chief Executive Officer of The St. Paul Companies, Inc.; H. Furlong Baldwin, Chairman of Mercantile Bankshares Corporation; Jonathan F. Bank, Senior Vice President of Tawa Associates Ltd.; Dan R. Carmichael, President and Chief Executive Officer of Ohio Casualty Corporation; and Peter T. Pruitt, retired Chairman of Willis Re Inc.

Our Competitive Strengths

        We believe that with our experienced management team, unencumbered capital base and the long-term potential of the business and assets of St. Paul Re obtained from St. Paul, we will have the benefits of being both an established business and a new market entrant. As a well-capitalized, focused reinsurer, we believe we will be able to expand our relationships with clients of St. Paul Re as well as new clients to a greater extent than if our operations were part of a multi-line insurer such as St. Paul.

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        We intend to focus our initial marketing efforts on those brokers and their clients with which St. Paul Re has established business relationships. We feel that the existing portfolio of business generated by St. Paul Re represents a valuable asset given the renewal nature of the reinsurance industry and the importance of continuity of relationships. We believe that the market perceptions and reputation established by St. Paul Re with respect to service and responsiveness will benefit us in light of the transfer of personnel and underwriting activities from St. Paul Re to us.

Platinum's Strategy

        Our goal is to achieve superior long-term returns for our shareholders, while establishing Platinum as a conservative risk manager and market leader in certain classes of property and casualty reinsurance.

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Build our future on a strong foundation. We will commence operations with the benefit of the Transferred Business:



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Renewal Rights and Assumed Reinsurance Contracts. Our initial portfolio will contain a diversity of business that would normally take many years to develop. We will be acquiring St. Paul Re's existing customer lists and the right to seek to renew its continuing in-force reinsurance contracts, which produced 2001 pro forma net premiums written of approximately $1.4 billion.



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Fully operational infrastructure. We will select experienced employees from the skilled St. Paul Re employee base. These employees have broker and ceding company relationships and underwriting pricing and claims experience that will allow us to be fully staffed and operational in key underwriting and support functions.




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Add new executive leadership to existing talent. In order to take full advantage of the historical strengths of St. Paul Re, we have significantly strengthened our senior management team with the addition of Mr. Newman and Mr. Fadden. Mr. Newman and Mr. Fadden have extensive experience in leading publicly traded reinsurance companies and intend to implement a number of initiatives to create a more focused and more profitable reinsurance business.



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Focus on profitability, not market share. Our new management team intends to pursue a strategy that emphasizes underwriting discipline and profitability over market share. Key elements of this strategy will be prudent risk selection, appropriate pricing through strict underwriting discipline and increasing our writings of lines of business, which we believe will contribute to our long-term profitability.



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Exercise disciplined underwriting and risk management. We intend to exercise risk management discipline by (i) maintaining a diverse spread of risk in our book of business across products and geographic zones, (ii) focusing on excess-of-loss contracts as opposed to proportional contracts and (iii) reducing our aggregate catastrophe exposure.



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Operate a lean and expense-focused underwriting business. We believe a lean underwriting culture will support our focus on profitability and allow us to be more responsive to changing market conditions. We intend to keep our headcount low and maintain a limited number of offices. In addition, we expect to originate most of our business from brokers, rather than directly from ceding companies or cedents, which are insurance companies seeking reinsurance coverages, which we believe will keep our expenses low.




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Grow our business by leveraging our global platform. We intend to operate in all three of the world's leading reinsurance markets with offices in New York, London and Bermuda.

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St. Paul Re has conducted authorized reinsurance activities in the United States and London for many years. Our new Bermuda subsidiary will provide us with both a new market in which to write reinsurance and the flexibility to provide reinsurance products that are best facilitated by an offshore company.

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Operate from a position of financial strength. As a newly formed company, our initial capital position is unencumbered by any development of loss reserves for business written prior to January 1, 2002, which are reserves established to reflect estimated cost of loss payments that ultimately will be required to be paid. Upon completion of the Equity Public Offering, the ESU Offering, the St. Paul Investment and the RenaissanceRe Investment, we expect to have a total capitalization of between approximately $955 million (assuming an initial public offering price of $22.00, a Cash Contribution of $121 million and no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares or the underwriters' option to purchase additional equity security units) and approximately $1,142 million (assuming an initial public offering price of $23.00, a Cash Contribution of $126 million and full exercise of the underwriters', St. Paul's and RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering and the underwriters' option to purchase additional equity security units). Our investment strategy will focus on security and stability in our investment portfolio by maintaining a diversified portfolio that will consist primarily of investment grade fixed-income securities.

Recent Industry Trends

        After an extended period of increased competition and eroding premiums, the reinsurance markets began experiencing improvements in rates, terms and conditions in the first quarter of 2000. These improvements continued in 2001 and were accelerated by the terrorist attack of September 11, 2001, which resulted in a range of estimated property and casualty insurance losses to the insurance industry of between $30 billion and $35 billion, the largest estimated catastrophe losses ever experienced by the industry. We believe property and other reinsurance premiums have often risen in the aftermath of significant catastrophe losses. As claims are reserved, industry surplus is depleted and the industry's capacity to write new business diminishes. At the same time, there appears to be heightened awareness that commercial properties are exposed to a variety of risks. We believe that market trends similar to those that have occurred in past cycles are developing in the current environment. With respect to January, April and July 2002 renewals, St. Paul Re experienced substantial rate increases, generally ranging from 20% to 50% depending on the line of business. We believe that the current imbalance between the increased demand for property-related insurance and reinsurance and the reduced supply of this type of coverage will continue at least for the immediate future.

St. Paul's Share Ownership

        St. Paul has determined that the efficiency, profitability and competitive position of its reinsurance operations can be maximized by separating them from St. Paul's primary insurance operations. Despite the separation of the two businesses, St. Paul will continue to participate in future financial results of the reinsurance business through its ownership of Common Shares as a result of the St. Paul Investment.

        In return for the Cash Contribution and the Transferred Business, we will issue 6,000,000 Common Shares to St. Paul (so that St. Paul will own 15.0% of our outstanding Common Shares following the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment) and the St. Paul Option. St. Paul's Common Shares will be limited to 9.9% of the voting power of the outstanding Common Shares. If the underwriters exercise their option to purchase additional

9

Common Shares in the Equity Public Offering, St. Paul will have the option to purchase additional Common Shares at a price per share equal to the initial public offering price less the underwriting discount in order for it to retain its 15.0% interest. In addition, we will grant St. Paul the St. Paul Option, which is a ten-year option to purchase up to 6,000,000 Common Shares at 120% of the initial public offering price for the Equity Public Offering. Exercise of such option by St. Paul in full immediately after completion of the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment would increase its percentage interest in our Common Shares to approximately 26.1%, assuming no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering or of the RenaissanceRe Option. However, St. Paul has agreed with us that, prior to any exercise of the St. Paul Option, it will, if necessary, dispose of a sufficient number of Common Shares so that, immediately after exercise of the St. Paul Option, St. Paul would not be a "United States 25% Shareholder" as defined under "Description of Platinum Holdings' Common Shares—Restrictions on Transfers." St. Paul has informed us that it currently intends to continue its share ownership in Platinum Holdings for the foreseeable future.

RenaissanceRe's Share Ownership and Business Arrangements

        In connection with the RenaissanceRe Investment, we will issue to RenaissanceRe 3,960,000 Common Shares (so that RenaissanceRe will own 9.9% of our outstanding Common Shares following the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment) and the RenaissanceRe Option. If the underwriters exercise their option to purchase additional Common Shares in the Equity Public Offering, RenaissanceRe will have the option to purchase additional Common Shares at a price per share equal to the initial public offering price less the underwriting discount, in order for it to retain its 9.9% interest. In addition, we will grant RenaissanceRe the RenaissanceRe Option, which is a ten-year option to purchase up to 2,500,000 Common Shares at 120% of the initial public offering price of the Equity Public Offering. Exercise of such option by RenaissanceRe in full immediately after completion of the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment would increase its percentage interest in Platinum Holdings' Common Shares to approximately 15.2%, assuming no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering or of the St. Paul Option. RenaissanceRe has agreed with us that, prior to any exercise of the RenaissanceRe Option, it will, if necessary, dispose of a sufficient number of Common Shares so that, immediately after exercise of the RenaissanceRe Option, RenaissanceRe would not beneficially own more than 19.9% of our outstanding voting securities (or up to 24.9% with our approval). See "Description of Platinum Holdings' Common Shares—Restrictions on Transfers." RenaissanceRe has informed us that it currently intends to continue its share ownership in Platinum Holdings for the foreseeable future.

        We have entered into an investment agreement with St. Paul and RenaissanceRe, which provides RenaissanceRe with, among other things, the right to nominate one director to our Board of Directors and, in addition, to designate a non-voting representative to attend our Board of Directors meetings, subject to certain conditions.

        We also will enter into an agreement, which we refer to as the "Services and Capacity Reservation Agreement" in this prospectus, with RenaissanceRe, pursuant to which in exchange for certain payments by us to RenaissanceRe, RenaissanceRe will provide services to us in connection with the reviewing and repositioning of our property catastrophe book of business for a period of five years. These services will include assisting us in measuring risk and managing our aggregate catastrophe exposures. In addition, we expect that we and RenaissanceRe may refer business to each other, to be accepted in the discretion of the party receiving the referral, and that compensation will be paid for referral business at negotiated rates.

        RenaissanceRe is a Bermuda company principally engaged, through its operating subsidiaries, in providing reinsurance and insurance coverage that is subject to the risk of natural and man-made catastrophes. For a further discussion of our relationship with RenaissanceRe, see "Certain Relationships and Related Transactions—The RenaissanceRe Investment."

Principal Executive Offices

        Platinum Holdings was organized on April 19, 2002 as a company limited by shares under Bermuda law. Platinum Holdings' principal executive offices are located at Clarendon House, 2 Church Street, Hamilton HM 11, Bermuda. Its telephone number is (441) 295-5950.

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The ESU Offering

What are the equity security units?

        Each equity security unit, which we refer to as a "unit", will initially consist of and represent:

        (1) a purchase contract pursuant to which:

•

you will agree to purchase, and Platinum Holdings will agree to sell, for $25, Common Shares on                          , 2005 (the "share purchase date"), the number of which will be determined based on the average trading price of the Common Shares for a period preceding that date, calculated in the manner described below; and

•

Platinum Holdings will pay you contract adjustment payments on a quarterly basis at the annual rate of    % of the stated amount of $25, subject to its right to defer such payments, as specified below; and

        (2) a 1/40, or 2.5%, ownership interest in a senior note due            , 2007 of Platinum Finance, an indirect, wholly owned subsidiary of Platinum Holdings, with a principal amount of $1,000, on which Platinum Finance will pay interest at the initial annual rate of    % until a successful remarketing of the senior notes and at the reset rate (as described below) thereafter. Interest will be payable quarterly in arrears through and including the share purchase date and, thereafter, semi-annually in arrears. The senior notes will be guaranteed by Platinum Holdings on a senior, unsecured basis.

        The ownership interests in the senior notes that are a component of your units will be owned by you, but will initially be pledged to the collateral agent for the benefit of Platinum Holdings to secure your obligations under the related purchase contracts. We refer in this prospectus to the purchase contracts, together with the pledged ownership interest in the senior notes (or, after a successful remarketing, a tax event redemption or prepayment in full of the senior notes described below, the specified pledged treasury securities), as "normal units."

        Each holder of normal units may elect at any time on or before the second business day prior to the share purchase date (subject to certain exceptions) to withdraw from the pledge the pledged ownership interest in the senior notes (or, after a successful remarketing or tax event redemption described below, the pledged treasury securities) underlying the normal units, thereby creating "stripped units." To create stripped units, the holder must substitute, as pledged securities, specifically identified treasury securities that will pay $25 (the amount due under the purchase contract) per unit on the share purchase date, and the pledged ownership interest in the senior notes or treasury securities will be released from the pledge and delivered to the holder. Holders of stripped units may recreate normal units by re-substituting the senior notes (or, after a successful remarketing or a tax event redemption, the applicable treasury securities) for the treasury securities underlying the stripped units.

        If the senior notes are successfully remarketed or a tax event redemption occurs, in each case as described in this prospectus, the applicable ownership interest in the treasury securities will replace the ownership interest in a senior note as a component of each unit and will be pledged to the collateral agent for the benefit of Platinum Holdings to secure your obligations under the purchase contract.

What are the purchase contracts?

        The purchase contract underlying a unit obligates you to purchase, and Platinum Holdings to sell, for $25, on the share purchase date, a number of newly issued Common Shares equal to the settlement rate described below. The settlement rate will be based on the average trading price of the Common Shares for a period preceding that date, calculated in the manner described below.

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What payments will be made to holders of the units and the senior notes?

        If you hold normal units, Platinum Holdings will pay you quarterly contract adjustment payments on the underlying purchase contracts at the annual rate of     % of the $25 stated amount through and including the share purchase date and Platinum Finance will pay you quarterly interest payments on the ownership interests in senior notes that are pledged in respect of your normal units at the initial annual rate of    % through and including            , 2005, the last quarterly payment date before the share purchase date. On the share purchase date, you will also receive a cash payment in respect of each of your normal units, equal to 1/40, or 2.5%, of the quarterly interest payment payable on the $1,000 principal amount of a senior note at the initial annual rate of    % unless the senior notes shall have been prepaid in full prior to a successful remarketing.

        If you hold stripped units and do not separately hold senior notes, you will receive only the quarterly contract adjustment payments payable by Platinum Holdings at the annual rate of     % of the $25 stated amount.

        The contract adjustment payments on normal and stripped units are subject to Platinum Holdings' deferral right as described below. Platinum Finance is not entitled to defer interest payments on any senior notes, whether held as part of, or separately from, the units.

        If you hold senior notes separately from the units and do not separately hold stripped units, you will receive only the interest payable on the senior notes. The senior notes, whether held separately from or as part of the units, will pay interest at the initial annual rate of            % until the settlement date of a successful remarketing, as described below. If the senior notes are successfully remarketed, the rate of interest payable from the settlement date of the successful remarketing until their maturity on            , 2007 will be the reset rate, which will be a rate established by the remarketing agent that meets the requirements described in this prospectus. If the remarketing agent cannot establish a reset rate on a remarketing date, the remarketing agent will not reset the interest rate on the senior notes and the interest rate will continue to be the initial annual rate of    %, until the remarketing agent, on a later remarketing date prior to the share purchase date, can establish a reset rate meeting the requirements described in this prospectus.

        Both Platinum Finance and Platinum Holdings are holding companies with no operations of their own. Although Platinum Finance will retain a portion of the net proceeds of the offering sufficient to fund the interest payments due on the senior notes payable on or prior to the share purchase date, the ability of Platinum Finance and Platinum Holdings to pay their respective obligations under the senior notes and the guarantee otherwise depends on their ability to obtain cash dividends or other cash payments or obtain loans from their subsidiaries, which are separate and distinct legal entities that will have no obligations to pay any dividends or to lend or advance them funds and which may be restricted from doing so by other financing arrangements, charter provisions or regulatory requirements. Platinum Finance's and Platinum Holdings' obligations under the senior notes and the guarantee will be effectively subordinated to the debt and other obligations of their respective subsidiaries. As of June 30, 2002, on a pro forma basis, Platinum Finance's subsidiaries had no liabilities or obligations that would have effectively ranked senior to the senior notes and Platinum Holdings' subsidiaries had approximately $270 million in liabilities and obligations that would have effectively ranked senior to the guarantees.

What are the payment dates?

        Subject to Platinum Holdings' deferral right in respect of the contract adjustment payments described below, contract adjustment payments will be made quarterly in arrears on each                      ,                       ,                       and                       , commencing on                      2003 and ending on the share purchase date. Interest payments on the senior notes initially will be made quarterly in arrears on each                      ,                       ,                       and                       , commencing

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on                      2003, and, following the share purchase date, semi-annually in arrears on each                      and                       until maturity on                      , 2007.

When can Platinum Holdings and Platinum Finance defer payments?

        Platinum Holdings can defer payment of all or part of the contract adjustment payments on the purchase contracts until no later than the share purchase date. Platinum Holdings will accrue additional contract adjustment payments on any deferred installments of contract adjustment payments at a rate of    % per year until paid, compounded quarterly, to but excluding the share purchase date, unless your purchase contract has been earlier settled or terminated.

        Platinum Finance is not entitled to defer interest payments on the senior notes.

What is the reset rate?

        In order to facilitate the remarketing of the senior notes at the remarketing price described below, the remarketing agent will reset the rate of interest on the senior notes, effective from the settlement date of a successful remarketing until their maturity on            , 2007. The reset rate will be the rate sufficient to cause the then current market value of each outstanding senior note to be equal to at least 100.25% of the remarketing value described below. Resetting the interest rate on the senior notes at this rate is designed to enable the remarketing agent to remarket the senior notes in the remarketing and purchase the necessary treasury securities, the proceeds of which will be applied in settlement of the purchase contracts and to provide funds for the cash payment on the normal units due on the share purchase date.

        The reset rate will be determined by the remarketing agent on the third business day (as defined below) prior to            , 2005, the last quarterly payment date before the share purchase date. If the remarketing agent cannot establish a reset rate meeting these requirements on the remarketing date and, as a result, the senior notes cannot be remarketed as described below, the interest rate will not be reset and will continue to be the initial rate of the senior notes. However, the remarketing agent may thereafter attempt to establish a reset rate meeting these requirements, and the remarketing agent may attempt to remarket the senior notes, on the subsequent dates described below. If a reset rate cannot be established on a given date, the remarketing will not occur on that date. If the remarketing agent fails to remarket the senior notes that form part of normal units by the end of the third business day immediately preceding the share purchase date, Platinum Holdings will exercise its rights as a secured party with respect to such senior notes and, subject to applicable law, may retain the pledged senior notes or sell them in one or more public or private sales to satisfy in full such holder's obligation to purchase Common Shares under the related purchase contracts.

        The reset of the interest rate on the senior notes in connection with a successful remarketing will not change the amount of the cash payment due to holders of normal units on the share purchase date, which, as described above, will be an amount per normal unit equal to 1/40, or 2.5%, of the quarterly interest payment payable on $1,000 principal amount of a senior note at the initial annual rate of            %.

        "Business day" means any day that is not a Saturday, Sunday or day on which banking institutions and trust companies in the State of New York or in the city where the principal corporate trust office of the collateral agent is located or at a place of payment are authorized or required by law, regulation or executive order to close. Platinum Holdings has initially appointed State Street Bank and Trust Company, whose principal corporate trust office is located in Boston, Massachusetts, to act as collateral agent.

        The reset rate may not exceed the maximum rate, if any, permitted by applicable law.

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What is remarketing?

        The remarketing agent will attempt to remarket the senior notes of holders of normal units and will use the proceeds to purchase treasury securities, which the participating holders of normal units will pledge to secure their obligations under the related purchase contracts. Holders of normal units may elect not to participate in any remarketing by following the procedures described below. The cash paid upon maturity of the pledged treasury securities underlying the normal units of such holders will be used to satisfy such holders' obligations to purchase Common Shares on the share purchase date, as well as to provide funds to make the cash payment to holders of normal units due on the share purchase date. This will be one way for holders of normal units to satisfy their obligations to purchase Common Shares under the related purchase contracts. The remarketing agent will attempt to remarket the senior notes that are included in normal units on one or more occasions starting on the remarketing date, which will be the third business day prior to            , 2005 or, if the remarketing agent fails to remarket the senior notes on that date, a later date as described below. As described below, a holder of a senior note in which interests are not held as part of normal units may elect to have the separately held senior note remarketed along with the senior notes in which interests are held as part of the normal units.

        Platinum Holdings and Platinum Finance will enter into a remarketing agreement with a nationally recognized investment banking firm that will act as remarketing agent. It is currently anticipated that Goldman, Sachs & Co. will be the remarketing agent. The remarketing agent will agree to use commercially reasonable best efforts to remarket the senior notes that are included in normal units (or separately held senior notes) that are participating in the remarketing, at a price per senior note equal to at least 100.25% of the remarketing value. The "remarketing value" of a senior note will be equal to the sum of:

        (1) the value at the remarketing date (or any subsequent remarketing date) of such amount of treasury securities that will pay, on or prior to the share purchase date, an amount of cash equal to the interest payment scheduled to be payable on the senior note on that date, assuming for this purpose, even if not true, that the interest rate on the senior notes remains at the initial rate; and

        (2) the value at the remarketing date (or any subsequent remarketing date) of such amount of treasury securities that will pay, on or prior to the share purchase date, an amount of cash equal to the principal amount of the senior note.

        The remarketing agent will use the proceeds from a successful remarketing of the senior notes included in normal units to purchase, in its discretion, the amount and the types of treasury securities described in (1) and (2) above in respect of each such senior note that has been remarketed. The remarketing agent will purchase such treasury securities in open market transactions or at treasury auction and deliver them through the purchase contract agent to the collateral agent to secure the obligations under the related purchase contracts of the holders of the normal units whose senior notes participated in the remarketing. The remarketing agent will deduct out of the proceeds in excess of the remarketing value as a remarketing fee an amount not exceeding 25 basis points (0.25%) of the total proceeds from such remarketing. The remarketing agent will remit the remaining portion of the proceeds, if any, for payment to the holders of the normal units participating in the remarketing.

        A holder of normal units may elect not to participate in any remarketing and, instead, retain the ownership interests in senior notes underlying those normal units by delivering, in respect of each senior note to be retained, the treasury securities having the value described in (1) and (2) above, in the amount and the types specified by the remarketing agent, to the purchase contract agent on the fourth business day prior to the first day of a remarketing period (as defined below) to satisfy its obligations under the related purchase contracts. Whether or not a holder of normal units

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participates in the remarketing, the interest rate on the senior notes in which interests are included in those units will nevertheless be reset if the remarketing is successful.

        Prior to any remarketing, Platinum Finance and Platinum Holdings plan to file and obtain effectiveness of a registration statement if so required under the U.S. federal securities law at the time.

What happens if the remarketing agent does not successfully remarket the senior notes on the remarketing date?

        If the remarketing agent cannot establish a reset rate meeting the requirements described above on the remarketing date and therefore cannot remarket the senior notes participating in the remarketing on the remarketing date at a price per senior note equal to at least 100.25% of the remarketing value, the remarketing agent will attempt to establish a reset rate meeting these requirements on each of the two business days immediately following the initial proposed remarketing date. If the remarketing agent cannot establish a reset rate meeting these requirements on either of those days, it will attempt to establish such a reset rate on each of the three business days immediately preceding            , 2005. If the remarketing agent cannot establish such a reset rate during that period, it will further attempt to establish such a reset rate on the third business day immediately preceding the share purchase date. We refer to each of these periods as a "remarketing period." Any subsequent remarketing will be at a price per senior note equal to at least 100.25% of the remarketing value on the subsequent remarketing date. If the remarketing agent fails to remarket the senior notes underlying the normal units at that price by the end of the third business day immediately preceding the share purchase date, any holder of normal units that has not otherwise settled its purchase contracts in cash on the business day immediately preceding the share purchase date (but without regard to the notice requirements otherwise applicable to cash settlement) will be deemed to have directed Platinum Holdings to retain the securities pledged as collateral in satisfaction of the holder's obligations under the related purchase contracts and Platinum Holdings will exercise its rights as a secured party and may, subject to applicable law, retain or dispose of such securities to satisfy in full such holder's obligation to purchase Platinum Holdings' Common Shares under the related purchase contracts on the share purchase date. In no event will a holder of a purchase contract be liable for any deficiency between such proceeds and the purchase price for the Common Shares under the purchase contract.

If I am not a party to a purchase contract, may I still participate in a remarketing of my senior notes?

        Holders of senior notes in which interests are not included as part of normal units may elect to have their senior notes included in the remarketing in the manner described in "Description of the Equity Security Units—Optional Remarketing." The remarketing agent will use commercially reasonable best efforts to remarket the separately held senior notes included in the remarketing at a price per senior note equal to at least 100.25% of the remarketing value, determined on the same basis as for the other senior notes being remarketed. After deducting as a remarketing fee an amount not exceeding 25 basis points (0.25%) of the total proceeds from such remarketing, the remaining portion of the proceeds, if any, will be remitted for payment to the holders whose separate senior notes were remarketed in the remarketing. If a holder of senior notes elects to have its senior notes remarketed during any remarketing period but the remarketing agent fails to remarket the senior notes during such remarketing period, the senior notes will be promptly returned to the custodial agent for release to the holder at the end of that period.

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What is the settlement rate?

        The settlement rate is the number of newly issued Common Shares that Platinum Holdings is obligated to sell and you are obligated to purchase upon settlement of a purchase contract on the share purchase date.

        The settlement rate for each purchase contract, subject to adjustment under specified circumstances, will be as follows:

•

if the applicable market value, determined as described below, of the Common Shares is equal to or greater than $                                , the settlement rate will be            Common Shares per purchase contract;

•

if the applicable market value of the Common Shares is less than $                                but greater than $                                , the settlement rate will be equal to $25 divided by the applicable market value of the Common Shares per purchase contract; or

•

if the applicable market value of the Common Shares is less than or equal to $                                , the settlement rate will be             Common Shares per purchase contract.

        "Applicable market value" means the average of the closing price per Common Share on each of the 20 consecutive trading days ending on the third trading day immediately preceding the share purchase date.

        At the option of each holder, a purchase contract may be settled early by the early delivery of cash to the purchase contract agent, as described below, in which case the settlement rate will be            Common Shares per purchase contract.

Besides participating in a remarketing, how else can my obligations under the purchase contract be satisfied?

        Besides participating in the remarketing, your obligations under the purchase contract may also be satisfied:

•

if you have created stripped units or elected not to participate in the remarketing, by delivering and pledging specified treasury securities in substitution for your senior notes and applying the cash payments received upon maturity of those pledged treasury securities;

•

through the early delivery of cash to the purchase contract agent on or prior to the seventh business day prior to the share purchase date in the manner described in "Description of the Equity Security Units—Early Settlement";

•

by delivering cash on the business day prior to the share purchase date for settlement of the purchase contracts in the manner described in "Description of the Equity Security Units—Notice to Settle with Cash"; or

•

if Platinum Holdings is involved in a merger, acquisition or consolidation prior to the share purchase date in which at least 30% of the consideration for the Common Shares consists of cash or cash equivalents, through an early settlement of the purchase contract as described in "Description of the Equity Security Units—Early Settlement Upon Cash Merger."

        If a holder of a unit elects not to participate in a remarketing and does not give notice to the purchase contract agent that the holder intends to settle the purchase contract with cash on the share purchase date, Platinum Holdings will exercise its rights as a secured party in respect of the pledged securities to satisfy the holder's obligation to purchase Common Shares.

        In addition, the purchase contracts, Platinum Holdings' related rights and obligations and those of the holders of the units, including their rights to receive accumulated contract adjustment payments or deferred contract adjustment payments and obligations to purchase Common Shares,

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will automatically terminate upon the occurrence of Platinum Holdings' bankruptcy, insolvency or reorganization. Upon such a termination of the purchase contracts, the pledged senior notes or treasury securities will be released and distributed to you. If Platinum Holdings becomes the subject of a case under the federal bankruptcy code, a delay may occur as a result of the imposition of an automatic stay under the bankruptcy code and continue until the automatic stay has been lifted. The automatic stay will not be lifted until such time as the bankruptcy judge agrees to lift it and allows your collateral to be returned to you. Similarly, if Platinum Holdings becomes the subject of winding up proceedings under the Bermuda Companies Act 1981, a delay may result from the automatic stay of proceedings against Platinum Holdings and may continue until the court decides to lift the stay.

        If the purchase contract is settled early or is terminated as the result of Platinum Holdings' bankruptcy, insolvency or reorganization as described above, a holder will have no further right to receive any accrued contract adjustment payments or deferred contract adjustment payments.

Under what circumstances may Platinum Finance redeem the senior notes before they mature?

        If the tax laws change or are interpreted by the tax authorities or the courts in a way that adversely affects our tax consequences with respect to the senior notes, then Platinum Finance may elect to redeem the senior notes. If the senior notes are redeemed before a successful remarketing, the money received from the redemption will be used by the collateral agent to purchase a portfolio of zero-coupon U.S. treasury securities that mature on or prior to each payment date of the senior notes through the share purchase date, in an aggregate amount equal to the principal on the senior notes included in normal units and the interest that would have been due on such payment date on the senior notes included in normal units. For a holder of normal units, these treasury securities will replace the senior notes as the collateral securing such holder's obligations to purchase Common Shares under the purchase contracts. If your senior notes are not components of normal units, you, rather than the collateral agent, will receive the related redemption payment. If the senior notes are redeemed, then each unit will consist of a purchase contract for Common Shares and an ownership interest in the portfolio of treasury securities.

What is the maturity of the senior notes?

        The senior notes will mature on            , 2007.

What is the extent of Platinum Holdings' guarantee?

        Platinum Holdings will irrevocably guarantee the payment in full of the following:

•

interest payments that are required to be paid on the senior notes; and

•

the principal amount of the senior notes.

        The guarantee will be unsecured and rank equally in right of payment to all other senior unsecured debt of Platinum Holdings. Under "What payments will be made to holders of the units and the senior notes?" we explain the extent to which Platinum Holdings' obligations under the guarantee will be effectively junior to the debt and other obligations of its subsidiaries.

        The senior notes and the guarantee do not limit Platinum Holdings' or Platinum Finance's ability or the ability of their respective subsidiaries to incur indebtedness. This would include indebtedness that ranks equally with the senior notes and the guarantee.

What are the U.S. federal income tax consequences related to the units and senior notes?

        If you purchase units in the ESU Offering, you will be treated for U.S. federal income tax purposes as having acquired purchase contracts and ownership interests in the senior notes

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constituting those units, and by purchasing the units you agree to treat the purchase contracts and ownership interests in the senior notes in that manner for all tax purposes. In addition, you agree to treat the senior notes as indebtedness of Platinum Finance for all tax purposes. You must allocate the purchase price of the units between purchase contracts and ownership interests in the senior notes in proportion to their respective fair market values, which will establish your initial tax basis in each component of the units. Platinum Holdings and Platinum Finance expect to report the fair market value of each purchase contract as $0.00 and the fair market value of each senior note as $1,000 (or $25 for each 2.5% ownership interest in a senior note included in a normal unit).

        For U.S. federal income tax purposes, we intend to treat the senior notes as contingent payment debt instruments subject to the "noncontingent bond method" of accruing original issue discount. As discussed more fully under "U.S. Federal Income Tax Consequences—Senior Notes—Original Issue Discount", the effects of this method will be (1) to require you, regardless of your usual method of tax accounting, to use an accrual method with respect to interest on the senior notes, (2) to require you, for all accrual periods through             , 2005, and possibly thereafter, to accrue interest income in excess of distributions actually received by you, and (3) generally to result in ordinary rather than capital treatment of any gain or loss on the sale, exchange or disposition of an ownership interest in the senior notes or the units to the extent attributable to the senior notes.

        Because there is no statutory, judicial or administrative authority directly addressing the tax treatment of units or instruments similar to units, you are urged to consult your own tax advisor concerning the tax consequences of an investment in units. For additional information, see "U.S. Federal Income Tax Consequences."

What are the ERISA considerations?

        Plans subject to Title I of the U.S. Employee Retirement Income Security Act of 1974 ("ERISA") or Section 4975 of the Internal Revenue Code of 1986, as amended, may invest in the equity units subject to the considerations set forth in "ERISA Considerations."

Will the units be listed on a stock exchange?

        The normal units have been approved for listing, subject to notice of issuance, on the New York Stock Exchange under the symbol "PTP Pr M". We have no obligation and do not currently intend to apply for any separate listing of either the stripped units or the senior notes on any stock exchange.

What are the expected uses of proceeds from the offerings?

        We estimate that Platinum Finance will receive net proceeds from the ESU Offering of approximately $120 million, or $138 million if the underwriters' option to purchase additional units is exercised in full. We anticipate that Platinum Finance will retain $20 million of the net proceeds, or $23 million if the underwriters exercise their option to purchase additional equity security units in full, and contribute the rest to Platinum US, its wholly owned subsidiary. Platinum Finance intends to use the retained portion of the net proceeds of the offering to fund the interest payments on the senior notes payable on or prior to the share purchase date.

        Assuming the Common Shares are offered at an initial public offering price of $22.50 per Common Share (the midpoint of the range at which Platinum Holdings proposes to offer the Common Shares), the net proceeds from the Equity Public Offering are estimated to be between approximately $640 million (assuming no exercise of the underwriters' option to purchase additional Common Shares) and $736 million (assuming full exercise of the underwriters' option to purchase additional Common Shares). A portion of the net proceeds of the Equity Public Offering, the RenaissanceRe Investment and the Cash Contribution, currently estimated at approximately $10 million, will be retained by Platinum Holdings and the balance will be contributed to the capital of Platinum US (in an amount not less than $250 million, including the contribution of net proceeds of the ESU Offering described above), Platinum UK (in an amount not less than $150 million, upon its being licensed in the United Kingdom), Platinum Ireland (in an amount not less than $100 million, substantially all of which will be used to purchase a surplus note issued by Platinum US) and Platinum Bermuda (in an amount not less than $375 million).

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The ESU Offering—Explanatory Diagrams

        The following diagrams demonstrate some of the key features of the purchase contracts, normal units, stripped units and senior notes, and the transformation of normal units into stripped units and senior notes. The following diagrams assume that the senior notes are successfully remarketed, the interest rate on the senior notes is reset, there is no early settlement and the payment of contract adjustment payments is not deferred.

Purchase Contracts

•

Normal units and stripped units both include a purchase contract under which you agree to purchase Common Shares on the share purchase date.

•

The number of Common Shares to be purchased under each purchase contract will depend on the "applicable market value." The "applicable market value" means the average of the closing price per Common Share on each of the 20 consecutive trading days ending on the third trading day immediately preceding the share purchase date.

(1)

The "reference price" is $                        , which is the initial public offering price of the Common Shares.

(2)

The "threshold appreciation price" is $                                , which is            % of the reference price.

(3)

For each of the percentage categories shown, the percentage of the Common Shares to be delivered on the share purchase date to a holder of normal units or stripped units is determined by dividing

•

the related number of Common Shares to be delivered, as indicated in the footnote for each such category, by

•

an amount equal to $25, the stated amount of the unit, divided by the reference price.

(4)

If the applicable market value of the Common Shares is less than or equal to the reference price, the number of Common Shares to be delivered will be calculated by dividing the stated amount of $25 by the reference price.

(5)

If the applicable market value of the Common Shares is between the reference price and the threshold appreciation price, the number of Common Shares to be delivered will be calculated by dividing the stated amount of $25 by the applicable market value.

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(6)

If the applicable market value of the Common Shares is greater than or equal to the threshold appreciation price, the number of Common Shares to be delivered will be calculated by dividing the stated amount of $25 by the threshold appreciation price.

Normal Units

•

A normal unit will consist of two components as illustrated below:





•

After a successful remarketing or tax event redemption, the normal units will include specified treasury securities in lieu of the senior notes.





•

If you hold a normal unit, you will hold an ownership interest in a senior note and, after a successful remarketing or tax event redemption, an ownership interest in specified treasury securities, but will pledge that interest to the collateral agent for the benefit of Platinum Holdings to secure your obligations under the purchase contract.





•

If you hold a normal unit, you may also substitute a specified amount of treasury securities for the ownership interest in a senior note if you decide not to participate in the remarketing.

20

Stripped Units

•

A stripped unit consists of two components as illustrated below:





•

If you hold a stripped unit, you own a 1/40, or 2.5%, interest in the treasury security but will pledge it to the collateral agent for the benefit of Platinum Holdings to secure your obligations under the purchase contract. The treasury security is a zero-coupon U.S. treasury security (CUSIP No.            ) that matures on             , 2005.

21

Senior Notes

•

Senior notes will have the terms illustrated below:

•

If you hold an ownership interest in a senior note that is a component of a normal unit, you have the option to either:



•

allow the ownership interest in the senior note to be included in the remarketing process, the proceeds of which will be used to purchase treasury securities, if the remarketing is successful, which will be applied to settle the purchase contract; or



•

elect not to participate in the remarketing by delivering treasury securities in substitution for the ownership interest in the senior note, the proceeds of which will be applied to settle the related purchase contract.




•

If you hold a senior note that is not a component of a normal unit, you have the option to either:



•

continue to hold the senior note the rate of which will be reset, effective from the settlement date of a successful remarketing of the senior notes; or



•

deliver the senior note to the remarketing agent to be included in the remarketing.

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Transforming Normal Units into Stripped Units and Senior Notes

•

To create stripped units, you must substitute for the pledged ownership interest in the senior note (or, after a successful remarketing or tax event redemption, the pledged treasury securities) the specified zero-coupon U.S. treasury security that matures on            , 2005.



•

The pledged senior note or the pledged treasury securities will be released from the pledge and delivered to you.



•

The zero-coupon U.S. treasury security together with the purchase contract would then constitute a stripped unit. The senior note (or, after a successful remarketing, treasury securities), which was previously a component of normal units, is tradable as a separate security.



•

The transformation of normal units into stripped units and senior notes and the transformation of stripped units and senior notes into normal units may generally be effected only in integral multiples of 40 units, as more fully described in this prospectus. If, however, the senior notes constituting a part of the normal units have been replaced with treasury securities due to a successful remarketing or tax event redemption, the transformation of normal units into stripped units and the recreation of normal units from stripped units may be effected only in integral multiples of units such that both the treasury securities to be deposited and the treasury securities to be released are in integral multiples of $1,000, as more fully described in this prospectus.

23

        The following illustration depicts the transformation of 40 normal units into 40 stripped units and one $1,000 principal amount senior note.

•

After remarketing, the normal units will include ownership interests in specified U.S. treasury securities in lieu of an ownership interest in senior notes.



•

You can also transform stripped units and senior notes (or, after a successful remarketing or tax event redemption, treasury securities) into normal units. Following that transformation, the specified zero-coupon U.S. treasury security, which was previously a component of the stripped units, is tradable as a separate security.

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Selected Pro Forma Financial Information and Operating Data

        Financial information in this prospectus is presented in U.S. dollars and on the basis of U.S. GAAP unless otherwise indicated.

        In this prospectus, we are presenting unaudited pro forma financial information of Platinum Holdings with respect to the Transferred Business, contingent upon the completion of the Equity Public Offering. This pro forma financial information is based on the terms of the agreements between Platinum and St. Paul effecting the transfer of the Transferred Business, the material terms of which are described under "Certain Relationships and Related Transactions", which we refer to herein as the "Inception Agreements."

        We caution that the Platinum pro forma consolidated balance sheet and pro forma combined underwriting results presented herein are not indicative of the actual results that we expect to achieve once we commence operations. Many factors may cause our actual results to differ materially from the pro forma consolidated balance sheet and underwriting results including, but not limited to, the following:

•

Platinum's pro forma combined statement of underwriting results includes premium and loss development on business entered into prior to January 1, 2002. Under the Quota Share Retrocession Agreements, we are assuming no premium or loss development on business entered into prior to January 1, 2002. Therefore, our reported premiums written and earned and reported losses and loss adjustment expenses, which are the expenses of settling claims, in our initial years of operation could be substantially lower than as presented in Platinum's pro forma combined statement of underwriting results. As such, our reported results in our initial years of operation will not be subject to prior year development for periods prior to January 1, 2002.



•

Following the Equity Public Offering, we will report underwriting results under the Quota Share Retrocession Agreements for the period through the date of completion of the Equity Public Offering based on the application of retroactive reinsurance accounting, resulting in the premiums earned and losses incurred by St. Paul during such period being excluded from our statement of underwriting results. Due to this exclusion, following the Equity Public Offering, our reported 2002 premiums written and earned and our net underwriting results in 2002 could be substantially different than as presented in Platinum's pro forma combined statement of underwriting results.



•

Platinum's pro forma consolidated balance sheet reflects the inception of the Quota Share Retrocession Agreements assuming transferred balances as of June 30, 2002. Platinum's actual consolidated balance sheet will report transferred amounts determined as of 12:01 a.m. on the day immediately following the date of completion of the Equity Public Offering. Accordingly, underwriting gain or loss with respect to the Assumed Reinsurance Contracts for the period from January 1, 2002 through such date will be retained by St. Paul.



•

Although we expect to continue to be afforded the benefits of most of St. Paul Re's retrocessional reinsurance program through their expiration during 2002, we may enter into retrocessional reinsurance contracts with significantly different terms and conditions from those that have been made available to us from St. Paul Re and which form the basis of our initial operations.



•

The additional and reinstatement premiums, which are premiums charged for the restoration of the limit of a catastrophe contract to its full amount after payment of losses, recorded in 2001 by St. Paul Re's Finite Risk operating segment were primarily caused by losses relating to the September 11, 2001 terrorist attack. These additional and reinstatement premiums

25

were unusually high and not necessarily indicative of the recurring premium volume we expect to write in that business segment.

•

Platinum's pro forma financial statements continue to reflect the discounting of the liability for certain Assumed Reinsurance Contracts based on our current intention to make arrangements to permit such discounting. If we do not put such arrangements in place, reinsurance contracts of a similar type entered into in the future would be reported on an undiscounted basis.

Pro Forma Consolidated Balance Sheet Data

        We have prepared our unaudited pro forma consolidated balance sheet as of June 30, 2002 to reflect our initial capitalization in the amount of $120,000 and adjusted to reflect, among other things,

•

amounts reflecting (a) the receipt of approximately $725 million, representing the estimated net proceeds from the Equity Public Offering and the RenaissanceRe Investment based on an assumed initial public offering price of $22.50 per Common Share (the midpoint of the range at which Platinum Holdings proposes to offer the Common Shares), without giving effect to any exercise of the underwiters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering, (b) the redemption of the Common Shares that were issued at inception and capital contributed prior to the Equity Public Offering, (c) the payment of certain formation and organization expenses, as discussed in Note 2 and Note 12 on pages F-5 and F-13 of this prospectus, which total $5.1 million, of which $2.1 million has been expensed as of June 30, 2002, and (d) our entering into, and accruing for, the Services and Capacity Reservation Agreement as of June 30, 2002. Additional formation and organization expenses will be incurred prior to closing. It is further assumed that the net proceeds from the Equity Public Offering will be invested in long-term, taxable fixed income securities;



•

amounts representing the receipt of St. Paul's Cash Contribution of $123 million (the midpoint of the $121 million to $126 million range for the Cash Contribution) and the contribution of the Transferred Business at historical cost in exchange for the issuance of Common Shares and the St. Paul Option. Amounts related to net tangible assets contributed to Platinum by St. Paul are recorded at St. Paul's book value as of June 30, 2002. Assets as of June 30, 2002 include approximately $5 million of net assets of Platinum US consisting of cash and cash equivalents (which reflect a dividend of $15 million to be paid, prior to completion of the Equity Public Offering, to United States Fidelity and Guaranty Company, the current parent of Platinum US) as well as approximately $7 million of tangible assets and other intangible assets such as broker and customer lists and contract renewal rights and licenses;



•

amounts reflecting the receipt of approximately $120 million, representing the estimated net proceeds from this offering and recognition of the present value of future contract adjustment payments payable on the purchase contracts contained within the equity security units, without giving effect to any exercise of the underwriters' option to purchase additional equity security units. It is further assumed that the net proceeds from this offering will be invested in long-term, taxable fixed income securities; and



•

amounts reflecting Platinum entering into the Quota Share Retrocession Agreements with St. Paul Re reinsuring the Assumed Reinsurance Contracts as of June 30, 2002.

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(1)

Reflects Platinum entering into, and accruing for, the Services and Capacity Reservation Agreement as of June 30, 2002.

(2)

Reflects senior notes issued in connection with the ESU Offering.

(3)

Reflects the present value of the contract adjustment payments in connection with the ESU Offering.

(4)

Reflects the issuance of 40,000,000 Common Shares in the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment.

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Pro Forma Combined Underwriting Results

        We have prepared our unaudited pro forma combined statements of underwriting results to represent our reinsurance business as if we had commenced our operations and the Equity Public Offering, the ESU Offering, the St. Paul Investment and the RenaissanceRe Investment had been completed as of January 1, 2001. Our presentation of our pro forma underwriting results assumes that all of the Inception Agreements were entered into as of January 1, 2001. We have based our presentation on St. Paul Re's actual underwriting results for the periods presented. We have then adjusted these historical results to remove any of St. Paul Re's reinsurance businesses that will not be part of Platinum following the completion of the Equity Public Offering, including:

•

amounts related to St. Paul Re's reinsurance business representing lines of business that will not be transferred to Platinum, including aviation and bond and credit reinsurance, certain financial risk and capital markets reinsurance products, and certain North American business previously underwritten in London. Platinum will not obtain the renewal rights to these lines of business and will not assume liabilities related to these lines of business, and Platinum's management does not intend to write these lines of business in the future; and



•

amounts related to St. Paul Re's allocations from the St. Paul corporate aggregate excess-of-loss reinsurance programs that will not be available to Platinum.

        Except as noted above, the pro forma combined underwriting results assume that all other retrocessional reinsurance with respect to the Assumed Reinsurance Contracts entered into in 2002 and prior years will remain available to Platinum.

        Also, as noted above, we have based our pro forma underwriting results on the assumption that all of the Inception Agreements were entered into on January 1, 2001, including the Services and Capacity Reservation Agreement.

        Our future results will depend in part on the amount of our investment income, which cannot be predicted and which will fluctuate depending upon the types of investments we select, our underwriting results and market factors. Actual tax expense in future periods will be based on underwriting results plus investment income and other income and expense items not reflected in the pro forma combined underwriting results. Our effective tax rate will reflect the proportion of income recognized by our operating subsidiaries, with Platinum US taxed at the U.S. corporate income tax rate (35%), Platinum UK taxed at the U.K. corporate tax rate (generally 30%), Platinum Ireland taxed at the Irish corporate tax rate (25% on non-trading income and 16% on trading income, the latter rate to be reduced to 12.5% as of January 1, 2003), and Platinum Bermuda taxed at a zero corporate tax rate. In 2002, we expect to have a greater portion of our income subject to U.S. taxation and U.K. taxation than we expect to have in the future because our Bermuda operations are entirely new but can be expected to grow as a proportion of our business. As a result of changes in the geographic distribution of taxable income as well as changes in the amount of our non-taxable income and expense, the relationship between our reported income before tax and our income tax expense may change significantly from one period to the next.

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(1)

Excludes ceded losses under St. Paul Re's aggregate excess-of-loss treaties, because such treaties extend to non-catastrophic as well as catastrophic losses as described below. The 3% benefit from catastrophes on the June 30, 2002 combined ratio is driven by a lack of catastrophes in the first six months of 2002 and favorable loss development in 2002 on catastrophe losses incurred in prior years.

        Included in the 2001 pro forma combined underwriting results are pre-tax losses related to the September 11, 2001 terrorist attack totaling $468 million. This amount includes gross losses and loss adjustment expenses of $819 million, $123 million of ceded reinsurance, $137 million of additional and reinstatement premiums and $91 million of reduced contingent commission expenses. The determination of the impact of catastrophes on the combined ratio (which is a combination of the expense ratio and the loss ratio) excludes the ceded losses under St. Paul Re's aggregate excess-of-loss treaties; these treaties provide coverage for excess losses arising from catastrophic and non-catastrophic events. The benefits of St. Paul Re's aggregate excess-of-loss treaty for 2002 will remain available to Platinum for the balance of 2002 unless earlier terminated pursuant to its terms.

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Pro Forma Underwriting Results by Operating Segment

        The following provides a summary of the pro forma underwriting results for our three operating segments. To provide a more meaningful indication of the underlying performance of our business segments, the results exclude the impact of St. Paul Re's aggregate excess-of-loss treaties and the impact of the September 11, 2001 terrorist attack.

Recent Developments

        See "Recent Developments" and "The Predecessor Business—Recent Developments" in this prospectus.

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RISK FACTORS

        Before investing in the units, you must carefully consider the following risk factors. These risks could materially affect our business, results of operations or financial condition and cause the trading price of the units to decline. You could lose part or all of your investment.

Risks Related to Our Business

If we are unable to implement our business strategy or operate our business as we currently expect, our results may be adversely affected.

        Platinum Holdings, Platinum UK, Platinum Bermuda, Platinum Ireland and Platinum Finance were recently formed. Platinum US, a wholly owned subsidiary of St. Paul, has been in existence since 1995 as an inactive insurance company. None of these companies has any operating history. Businesses, such as ours, which are starting up or in their initial stages of development, present substantial business and financial risks and may suffer significant losses. We must develop business relations, establish operating procedures, hire staff, obtain facilities, implement new systems, obtain licenses and complete other tasks appropriate for the conduct of our intended business activities. If we are unable to implement these actions to operate our business as we currently expect, our results may be adversely affected. As a result of industry factors or factors specific to Platinum, we may have to alter our anticipated methods of conducting our business, such as the nature, amount and types of risks we assume.

We may not be able to successfully continue the business being contributed by
St. Paul Re because we do not have St. Paul's established name recognition and capital base.

        Although we anticipate commencing our operations with an existing reinsurance business, including renewal opportunities, broker and cedent relationships, a workforce and other tangible and intangible assets that are being contributed by St. Paul Re, we may not be able to successfully continue this business. We will not have any of the benefits which may have flowed to the business from being affiliated with St. Paul, including its name recognition, its reputation in the industry and its strong capital base. In addition, we will not have certain offices that produced 2002 business but that were closed in late 2001 and early 2002. It is possible that clients of St. Paul Re will choose not to renew expiring contracts with us and will choose to reinsure with our competitors. It is possible that cedents will choose to not do business with us because we will have a smaller capital base or lower ratings than St. Paul has or because the cedents' credit approval committees will not approve doing business with us. It is possible that clients that do renew expiring contracts with us may demand policy terms that are less favorable to us or may renew only with reduced coverage limits. In addition, certain of the Assumed Reinsurance Contracts afford the reinsured party a right to cancel coverage upon transfer of the Transferred Business to us. While we expect that few, if any, cancellations will occur, substantial cancellations would adversely affect our future results of operations, particularly in the near term. We may not be able to maintain the broker relationships established by St. Paul Re, or retain those employees of St. Paul Re who are expected to join us upon completion of the Equity Public Offering. We may not be able to build upon this base of business or operate our business as successfully as St. Paul Re. It is also possible that the restructuring of St. Paul Re that St. Paul initiated in December 2001 and the Equity Public Offering and this offering may adversely affect our ability to maintain the St. Paul Re business that is being transferred to us.

Neither our pro forma financial information nor the historical combined financial information of St. Paul Re in this prospectus is an indicator of our future actual results.

        As a newly formed company, we have no actual results of operations. We are, therefore, presenting in this prospectus our pro forma financial information with respect to the reinsurance business which St. Paul will be transferring to us, as if the Equity Public Offering, this offering, the

31

St. Paul Investment and the RenaissanceRe Investment had been completed and we had commenced our operations as of January 1, 2001. We are also presenting historical combined financial information of St. Paul Re to illustrate the underwriting results of our actual historical reinsurance business.

        We caution that our pro forma financial information and the historical combined financial information of St. Paul Re presented in this prospectus are not necessarily comparable with or indicative of the actual results that we expect to achieve once we commence operations for the reasons set forth below:

•

Platinum's pro forma combined statement of underwriting results includes premium and loss development on business entered into prior to January 1, 2002. Under the Quota Share Retrocession Agreements, we are assuming no premium or loss development on business entered into prior to January 1, 2002. Therefore, our reported premiums written and earned and reported losses and loss adjustment expenses in our initial years of operation could be substantially lower than as presented in Platinum's pro forma combined statement of underwriting results. As such, our reported results in our initial years of operation will not be subject to prior year development for periods prior to January 1, 2002.

•

Following the Equity Public Offering, we will report underwriting results under the Quota Share Retrocession Agreements for the period through the date of completion of the Equity Public Offering based on the application of retroactive reinsurance accounting, resulting in the premiums earned and losses incurred by St. Paul during such period being excluded from our statement of underwriting results. Due to this exclusion, following the Equity Public Offering, our reported 2002 premiums written and earned and our net underwriting results in 2002 could be substantially different than as presented in Platinum's pro forma combined statement of underwriting results.

•

Platinum's pro forma consolidated balance sheet reflects the inception of the Quota Share Retrocession Agreements assuming transferred balances as of June 30, 2002. Platinum's actual consolidated balance sheet will report transferred amounts determined as of 12:01 a.m. on the day immediately following the date of completion of the Equity Public Offering. Accordingly, underwriting gain or loss with respect to the Assumed Reinsurance Contracts for the period from January 1, 2002 through such date will be retained by St. Paul.

•

Although we expect to continue to be afforded the benefits of most of St. Paul Re's retrocessional reinsurance program through their expiration during 2002, we may enter into retrocessional reinsurance contracts with significantly different terms and conditions from those that have been made available to us from St. Paul Re and which form the basis of our initial operations.

•

The additional and reinstatement premiums recorded in 2001 by St. Paul Re's Finite Risk operating segment were primarily caused by losses relating to the September 11, 2001 terrorist attack. These additional and reinstatement premiums were unusually high and not necessarily indicative of the recurring premium volume we expect to write in that business segment.

•

Platinum's pro forma financial statements continue to reflect the discounting of the liability for certain Assumed Reinsurance Contracts based on our current intention to make arrangements to permit such discounting. If we do not put such arrangements in place, reinsurance contracts of a similar type entered into in the future would be reported on an un-discounted basis.

        Our future consolidated financial results will also depend on the amount of our investment income, which cannot be predicted and which will fluctuate depending upon the types of

32

investments we select, our underwriting results and market factors, such as the level of interest rates, as well as our consolidated effective tax rate.

Intense competition could adversely affect our profitability.

        The property and casualty reinsurance industry is highly competitive and, except for regulatory considerations, there are relatively few barriers to entry. We will compete with major U.S. and non-U.S. reinsurers, including several Bermuda-based reinsurers that write property and casualty reinsurance and that target the same market as we do and utilize similar business strategies.

        In addition to reinsurance company competitors, other financial institutions are now able to offer services similar to those that we expect to offer. Financial institutions have also created alternative capital market products that compete with reinsurance products, such as reinsurance securitization. Such alternative products may be perceived to be more beneficial for ceding companies than reinsurance offered by reinsurance companies and may result in lower demand for certain of our products.

        Since we have no operating history, many of our competitors have greater name and brand recognition than we currently do. Many of them also have more (in some cases substantially more) capital and greater marketing and management resources than we expect to have, and may offer a broader range of products and more competitive pricing than we expect to or will be able to offer.

        Our competitive position will be based on many factors, including our perceived overall financial strength, ratings assigned by independent rating agencies, geographic scope of business, client relationships, premiums charged, contract terms and conditions, products and services offered (including the ability to design customized programs), speed of claims payment, reputation, experience and qualifications of employees and local presence. Since we have not yet commenced operations, we may not be able to compete successfully on any of these bases. If competition limits our ability to write new business at adequate rates, our return on capital may be adversely affected.

The September 11, 2001 terrorist attack has generated substantial new capital inflows into the reinsurance industry, increasing competition which could adversely affect our profitability.

        Following the terrorist attack of September 11, 2001, a number of new reinsurers and other entities have been formed and a number of existing market participants have raised new capital in an effort to participate in an improving marketplace. These new and better financed companies are expected to increase the level of competition in the industry, which may affect our competitive position. While we believe that we and our competitors will be able to raise premium rates in the near and intermediate term, the additional competition following the September 11, 2001 terrorist attack may limit such increases or result in decreases in premium rates.

We are not yet rated by A.M. Best and this could affect our competitive position with customers.

        Competition in the types of reinsurance business that we intend to underwrite is based on many factors, including the perceived financial strength of the reinsurer and ratings assigned by independent rating agencies. A.M. Best Company, Inc. ("Best's") is generally considered to be a significant rating agency with respect to the evaluation of insurance and reinsurance companies. Best's ratings are based on a quantitative evaluation of performance with respect to profitability, leverage and liquidity and a qualitative evaluation of spread of risk, reinsurance program, investments, reserves and management. Insurance ratings are used by insurers and reinsurance intermediaries as an important means of assessing the financial strength and quality of reinsurers. In addition, a ceding company's own rating may be adversely affected by the lack of a rating of its reinsurer. Therefore, the lack of a rating may dissuade a ceding company from reinsuring with us

33

and may influence a ceding company to reinsure with a competitor of ours that has an insurance rating.

        Our management has met with Best's, which has advised us that it expects to assign an initial financial strength rating of "A" (Excellent) to our operating subsidiaries upon the completion of the Equity Public Offering and the receipt of the offering proceeds in line with certain representations we made to Best's. In addition, the rating assignment is contingent upon the funding of our operating subsidiaries to the levels indicated by our management as well as the execution of all pertinent transactions as detailed by this prospectus. The rating assignment further contemplates the initiation of certain capital support agreements between Platinum Holdings and its operating subsidiaries.

        However, we may not obtain the "A" rating if we do not receive a sufficient amount of proceeds from the Equity Public Offering in order to capitalize our operating subsidiaries at the levels we indicated to Best's, execute the transactions described in this prospectus or otherwise satisfy the conditions set by Best's for the assignment to us of such a rating.

Consolidation in the insurance industry could lead to lower margins for us and less demand for our reinsurance products and services.

        The insurance industry is undergoing a process of consolidation as industry participants seek to enhance their product and geographic reach, client base, operating efficiency and general market power through merger and acquisition activities. These larger entities may seek to use the benefits of consolidation to, among other things, implement price reductions for their products and services. If competitive pressures compel us to reduce our prices, our operating margins would decrease.

        As the insurance industry consolidates, competition for customers may become more intense and the importance of acquiring and properly servicing each customer will become greater. We could incur greater expenses relating to customer acquisition and retention, which could reduce our operating margins. In addition, insurance companies that merge may be able to enhance their negotiating position when buying reinsurance and may be able to spread their risks across a consolidated, larger capital base so that they require less reinsurance.

We are dependent on key executives.

        Our success will depend in substantial part upon the continued service of Steven H. Newman as our Chairman of the Board of Directors and Jerome T. Fadden as our President and Chief Executive Officer. Mr. Fadden's employment contract will expire on March 4, 2007 unless extended. Mr. Newman will serve as a consultant to Platinum US through March 1, 2005 unless his consulting contract is extended. Our success will also depend on our ability to attract and retain additional executives and underwriting personnel. We believe that there are only a limited number of available, qualified executives in the reinsurance industry, and our inability to hire additional senior executives or the loss of the services of any of our senior executives could delay or prevent us from fully implementing our business strategy and could significantly and negatively affect our business.

        Under Bermuda law, non-Bermudians (other than spouses of Bermudians) may not engage in any gainful occupation in Bermuda without a work permit. None of our executive officers is a Bermudian, and all such officers will be working in Bermuda under work permits. Mr. Fadden has obtained a temporary work permit, and we are seeking longer-term work permits from the Bermuda authorities for him as well as for Michael E. Lombardozzi, William A. Robbie and any other persons who will be employees of Platinum Holdings or Platinum Bermuda who are not Bermudian citizens. The Bermuda government recently announced a new policy that places a six-year term limit on individuals with work permits, subject to certain exemptions for key employees. It is possible that we could lose the services of one or more of these people if we are unable to obtain or renew their work permits, which could significantly and adversely affect our business.

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The occurrence of severe catastrophic events may have a material adverse effect on our financial results and financial condition.

        Because we intend to underwrite property and casualty reinsurance and will have large aggregate exposures to natural and man-made disasters, we expect that our loss experience generally will include infrequent events of great severity. The frequency and severity of catastrophe losses are inherently unpredictable. Consequently, the occurrence of losses from catastrophic events is likely to cause a material adverse effect on our results of operations and financial condition. For example, St. Paul Re recorded pre-tax catastrophe losses of $135 million in 2000 and $143 million in 1999, materially impacting its results of operations during those years. In addition, catastrophes are an inherent risk of our business and a catastrophe or series of catastrophes can be expected to have a material adverse effect on our ability to write new business, and our financial condition and results of operations, possibly to the extent of eliminating our shareholders' equity and statutory surplus (which is the amount remaining after all liabilities, including loss reserves, are subtracted from all admitted assets, as determined under statutory accounting principles, which are the principles prescribed or permitted by U.S. insurance regulatory authorities). Increases in the values and geographic concentrations of insured property and the effects of inflation have historically resulted in increased severity of industry losses in recent years and we expect that those factors will increase the severity of catastrophe losses in the future.

        Under the Quota Share Retrocession Agreements, St. Paul retains recorded underwriting gain or loss with respect to the Assumed Reinsurance Contracts for the period from January 1, 2002 to the transfer date, which is 12:01 a.m. on the day immediately following the date of completion of the Equity Public Offering. In addition, St. Paul will retain all liabilities relating to the flooding in Europe in August 2002, which included $30 million in losses for the nine months ended September 30, 2002. With respect to "named storms" (which are Tropical Prediction Center-designated named storms) in existence at the time of the completion of the Equity Public Offering which cause insured damage within ten days subsequent to such time, we will bear losses of up to $25 million in the aggregate, net of recoveries from the retrocessional reinsurance purchased by St. Paul that inures to our benefit. St. Paul will bear losses in respect of such storms that are, in the aggregate, and net of recoveries, subject to specified exceptions, from such retrocessional reinsurance, in excess of $25 million up to $50 million. We also will bear all losses, in the aggregate and net of recoveries from such retrocessional reinsurance, in excess of $50 million in respect of such storms. We have purchased third-party retrocessional coverage in an amount up to $100 million for losses in excess of $50 million, in the aggregate, net of inuring retrocessions, with respect to damage that occurs during the 15-day period beginning at 12:01 a.m. the day of pricing of the Equity Public Offering, as a result of named storms in existence at that time but not yet in existence as of October 10, 2002. We will bear $2.5 million of the cost of this coverage, with St. Paul bearing the remainder of its cost.

        Accordingly, St. Paul retains underwriting losses, if any, with respect to catastrophes arising before the transfer date to the extent reserves are established therefor as of such date (as determined 90 days after such date). Platinum bears all underwriting loss from catastrophes occurring on or after the transfer date (other than the intermediate $25 million layer of coverage borne by St. Paul with respect to specified named storms, on the terms described above), and any underwriting loss or gain resulting from reestimation of catastrophe losses established by St. Paul as of the transfer date (other than with respect to the August 2002 European floods and the intermediate $25 million layer of coverage borne by St. Paul with respect to specified named storms, on the terms described above). Under the Quota Share Retrocession Agreements, premiums attributable to policy periods prior to the transfer date and future premiums with respect to flooding in Europe in August 2002 are retained by St. Paul, and premiums attributable to periods on or following the transfer date are for Platinum's benefit. Consistent with St. Paul's accounting practices, St. Paul and Platinum intend to allocate 2002 premiums attributable to catastrophe

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coverage before and after the transfer date between themselves on a pro rata basis over the applicable policy period, without adjustment for seasonality that exists for certain catastrophe losses. Certain catastrophic events, such as hurricane and windstorm exposure in North America, tend to occur more frequently in the latter half of the calendar year. Accordingly, Platinum's premium income attributable to certain catastrophe coverages and earned in the period following the time of effectiveness of the Quota Share Retrocession Agreements may not, due to seasonality among other factors, sufficiently match Platinum's exposure to losses from certain catastrophic events which may occur in the remaining part of 2002. As of the day prior to the date of this preliminary prospectus, there was one "named storm", which could cause us to be liable for substantial catastrophic losses immediately following the completion of the Equity Public Offering despite the sharing arrangement with St. Paul, and such number of "named storms" could increase or decrease prior to the date of the final prospectus for the Equity Public Offering or the completion of the Equity Public Offering itself.

The September 11, 2001 terrorist attack may result in government intervention impacting the insurance and reinsurance markets.

        In response to the tightening of supply in certain insurance markets resulting from, among other things, the terrorist attack of September 11, 2001, the U.S. government and other governments may intervene in the insurance and reinsurance markets. Following the September 11, 2001 terrorist attack, various proposed legislation that is designed to ensure the availability of insurance coverage for terrorist acts has been introduced in the U.S. Congress. Legislation has been adopted in the U.S. House of Representatives designed, among other things, to provide federal government loans over a short-term period to commercial insurers and reinsurers for funding losses arising from terrorist acts against U.S. properties, which loans would be repaid through industry assessments and, if losses exceed a threshold, policyholder assessments. Similar, alternative legislation has been adopted in the U.S. Senate; the Senate legislation provides for direct government assistance to commercial insurers and reinsurers for covered losses that exceed a per-company "deductible." We cannot predict whether any such legislation will be enacted or what form it may take. You should note that governmental intervention could significantly and adversely affect us by, among other things:

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providing competing insurance and reinsurance capacity in the markets and to the customers we expect to target;

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regulating the terms of insurance and reinsurance capacity and reinsurance policies in a manner that could significantly and adversely affect us, directly or indirectly, by requiring coverage for terrorist acts to be offered by insurers and reinsurers, benefiting our competitors, reducing the demand for our products or benefiting insurers as compared to reinsurers such as ourselves;

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providing sources of liquidity to U.S. companies that may not be available to our non-U.S. subsidiaries; or

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otherwise disproportionally benefiting U.S. or other foreign countries' companies over Bermuda-based companies such as Platinum Holdings and its Bermuda subsidiary.

The September 11, 2001 terrorist attack has caused uncertainty as to future insurance and reinsurance coverage for terrorist acts, and we may in the future have substantial exposure to such acts.

        Following the terrorist attack of September 11, 2001, there is uncertainty in the insurance and reinsurance markets about the extent to which future coverages will extend to terrorist acts. There is also uncertainty about the definition of terrorist acts. We believe that coverage of claims that are the result of terrorist acts (as they are ultimately defined by industry and government standards) will generally be excluded from property catastrophe reinsurance contracts covering large commercial

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risks above specified property values, but generally will not be excluded for smaller commercial coverages, personal lines written for individuals or families or other coverages. Accordingly, we presently continue to incur exposure to terrorist acts. The extent to which coverage for terrorist acts will be offered by the insurance and reinsurance markets in the future is uncertain. Coverage for losses resulting from terrorist acts may be offered separately in the reinsurance market, and we may or may not offer such coverage in the future. If our and the insurance industry's attempts to exclude terrorist acts from contracts covering large commercial risks that exceed specified values were to fail, we could incur large unexpected losses if further terrorist attacks occur.

The failure to be effective of any of the loss limitation methods we employ could have a material adverse effect on our financial condition or our results of operations.

        Our property and casualty reinsurance contracts cover unpredictable events such as hurricanes, windstorms, hailstorms, earthquakes, volcanic eruptions, fires, industrial explosions, freezes, riots, floods and other natural or man-made disasters. We intend to seek to limit our loss exposure by writing the majority of our products on an excess-of-loss basis. We also intend to limit the aggregate amount of all treaties for each client and to execute prudent underwriting of each program written. In the case of treaties where we reinsure a proportionate part of premiums and losses, which are referred to as pro rata or proportional treaties, we intend to seek per occurrence limitations or caps on the ratio of losses to premiums, which are referred to as loss cap ratios, to limit the impact of losses from any one event. A limited number of the Assumed Reinsurance Contracts do not contain these limits, which means that there is no contractual limit to the losses that we may be required to pay pursuant to such Assumed Reinsurance Contracts. In addition, we intend to seek to limit our loss exposure by geographic diversification. Geographic zone limitations involve significant underwriting judgments, including the specification of the areas constituting the zones and the inclusion of a particular policy within a particular zone's limits. Various provisions of our policies, such as limitations or exclusions from coverage or choice of forum, may not be enforceable in the manner we intend, due to, among other things, disputes relating to coverage and choice of legal forum. Underwriting is a matter of judgment, involving important assumptions about matters that are inherently unpredictable and beyond our control, and for which historical experience and probability analysis may not provide sufficient guidance. One or more catastrophic or other events could result in claims that substantially exceed our expectations, which could have a material adverse effect on our financial condition or our results of operations, possibly to the extent of eliminating our shareholders' equity and statutory surplus. St. Paul Re recorded net pretax losses of $556 million as a result of the September 11, 2001 terrorist attack, the most significant catastrophe to date for the property-casualty insurance industry. Contributing to the significance of these losses were certain contracts having occurrence limits that excluded natural perils but not man-made disasters. Had these occurrence limits excluded man-made disasters, St. Paul Re's losses would have been approximately $25 million lower.

We intend to purchase retrocessional reinsurance, which will subject us to credit risk and may become unavailable on acceptable terms.

        In order to limit the effect on our financial condition of large and multiple losses, we intend to buy retrocessional reinsurance, which is reinsurance for our own account. From time to time, market conditions have limited, and in some cases have prevented, insurers and reinsurers from obtaining the types and amounts of reinsurance which they consider adequate for their business needs. As a result of the September 11, 2001 terrorist attack, both pricing and terms have become more severe in the retrocessional reinsurance market, which may limit our ability to obtain desired amounts of retrocessional reinsurance at acceptable pricing. If we are unable to obtain retrocessional reinsurance, our financial position and results of operations may be materially adversely affected. Moreover, the September 11, 2001 terrorist attack, threats of further terrorist attacks and the military initiatives and political unrest in Afghanistan, the Middle East and the surrounding regions have adversely affected general economic, market and political conditions,

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increasing many of the risks of our business. Over time, the rating agencies could re-examine the ratings affecting our industry. We may not be able to obtain our desired amounts of retrocessional reinsurance on acceptable terms. St. Paul Re had retrocessional arrangements through St. Paul, and we may not be able to obtain replacement agreements. Even if we are able to obtain such retrocessional reinsurance, we may not be able to negotiate terms as favorable to us as the terms that St. Paul Re was able to obtain through St. Paul in prior years. Loss of all or portions of our retrocessional coverage could subject us to increased exposure, which could be material.

        A retrocessionaire's insolvency or its inability or unwillingness to make payments under the terms of its reinsurance treaty with us could have a material adverse effect on us. Therefore, our retrocessions subject us to credit risk because the ceding of risk to retrocessionaires does not relieve a reinsurer of its liability to the ceding companies.

If we are required to increase our loss reserves, our operating results will be adversely affected.

        At any time, our loss reserves may prove to be inadequate to cover our actual losses and benefits experience. To the extent loss reserves may be insufficient to cover actual losses or loss adjustment expenses, we will have to add to these loss reserves and incur a charge to our earnings, which could have a material adverse effect on our financial condition, results of underwriting and cash flows. St. Paul Re has experienced such instances where a re-estimation of loss reserves has proved to be material and, in 2001, recorded a net additional provision of $95 million related to losses incurred in prior years. This provision reflected worse than expected loss emergence in St. Paul Re's North American Property segment, largely driven by certain property business underwritten through its London office, and in the surplus lines business. We could experience adverse development on our loss reserves, including those initially established by St. Paul Re and transferred to us pursuant to the Quota Share Retrocession Agreements.

        Our loss reserves will not represent an exact calculation of liability, but rather will be estimates of the expected cost of the ultimate settlement of losses. We expect that all of our loss reserve estimates will be based on actuarial and statistical projections at a given time, of facts and circumstances known at that time and estimates of trends in loss severity and other variable factors, including new concepts of liability and general economic conditions. Changes in these trends or other variable factors could result in claims in excess of our loss reserves.

        Unforeseen losses, the type or magnitude of which we cannot predict, may emerge in the future. These additional losses could arise from changes in the legal environment, catastrophic events, extraordinary events affecting our clients such as reorganizations and liquidations or changes in general economic conditions.

        In addition, because we, like other reinsurers, will not separately evaluate each of the individual risks assumed under reinsurance treaties, we will be largely dependent on the original underwriting decisions made by ceding companies. We will be subject to the risk that our ceding companies may not have adequately evaluated the risks to be reinsured and that the premiums ceded to us may not adequately compensate us for the risks we assume.

        Under U.S. GAAP, Platinum US, Platinum UK and Platinum Bermuda will not be permitted to establish loss reserves until an event occurs which may give rise to a loss. Once such an event occurs, reserves will be established based upon estimates of the total losses incurred by the ceding insurers and an estimate of the portion of such loss our three operating subsidiaries have reinsured. As a result, only loss reserves applicable to losses incurred up to the reporting date may be set aside, with no allowance for the provision of a contingency reserve to account for expected future losses. Losses arising from future events will be estimated and recognized at the time the loss is incurred and could be substantial.

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The property and casualty reinsurance business is historically cyclical, and we expect to experience periods with excess underwriting capacity and unfavorable pricing.

        Historically, property and casualty reinsurers have experienced significant fluctuations in operating results. Demand for reinsurance is influenced significantly by underwriting results of primary insurers and prevailing general economic and market conditions, all of which affect cedents' decisions as to the amount or portion of risk that they retain for their own accounts and consequently reinsurance premium rates. The supply of reinsurance is related to prevailing prices, the levels of insured losses and levels of industry surplus which, in turn, may fluctuate in response to changes in rates of return on investments being earned in the reinsurance industry. As a result, the property and casualty reinsurance business historically has been a cyclical industry characterized by periods of intense price competition due to excessive underwriting capacity as well as periods when shortages of capacity permitted favorable premium levels. We can expect to experience the effects of such cyclicality.

        The cyclical trends in the industry and the industry's profitability can also be affected significantly by volatile and unpredictable developments, including what management believes to be a trend of courts to grant increasingly larger awards for certain damages, natural disasters (such as catastrophic hurricanes, windstorms, tornadoes, earthquakes and floods), fluctuations in interest rates, changes in the investment environment that affect market prices of and income and returns on investments and inflationary pressures that may tend to affect the size of losses experienced by primary insurance companies. Although market conditions have improved recently with respect to some lines of property and casualty reinsurance, we cannot predict whether market conditions will continue to improve, remain constant or deteriorate. A return to negative market conditions may affect our ability to write reinsurance at rates that we consider appropriate relative to the risk assumed. If we cannot write property and casualty reinsurance at appropriate rates, our ability to transact reinsurance business would be significantly and adversely affected.

A significant amount of our invested assets will be subject to market volatility.

        Our investment portfolio will consist initially of fixed income securities and, in the future, may include marketable equity securities. The fair market value of these assets and the investment income from these assets will fluctuate depending on general economic and market conditions. Fixed income and equity markets have become increasingly volatile in the last year and particularly since the events of September 11, 2001. Because substantially all of our invested assets will be classified as available for sale, changes in the market value of our securities will be reflected in our consolidated balance sheet. In addition, market fluctuations and market volatility will affect the value of our investment portfolio and could adversely affect our liquidity.

Increases in interest rates or fluctuations in currency exchange rates may cause us to experience losses.

        Because of the unpredictable nature of losses that may arise under reinsurance policies, our liquidity needs can be expected to be substantial and to arise at any time. The market value of our fixed income investments will be subject to fluctuation depending on changes in various factors, including prevailing interest rates. We expect to hedge our investment portfolio against interest rate risk. Nevertheless, increases in interest rates during periods when we sell fixed income securities to satisfy liquidity needs may result in losses.

        Our functional currency will be the U.S. dollar. Our operating currency generally will also be the U.S. dollar. However, the premiums receivable and losses payable in respect of a portion of our business will be denominated in currencies of other countries, principally the industrialized countries. Consequently, we may, from time to time, experience exchange gains and losses that could affect our financial position and results of operations. We do not expect to — and as a practical matter will not be able to — hedge our foreign currency exposure with respect to potential losses until a loss payable in a foreign currency occurs (after which we may match such liability

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with assets denominated in the same currency or enter into forward purchase contracts for specific currencies). This type of exposure could be substantial. We also do not intend to hedge our non- U.S. dollar currency exposure with respect to premiums receivable, which will be generally collected over the relevant contract term. We expect to exchange non-U.S. dollar denominated premiums upon receipt. We may make foreign currency denominated investments, generally for the purpose of improving overall portfolio yield.

Platinum UK will not be licensed in the United Kingdom at the time of completion of the Equity Public Offering, and any license, if obtained, may be subject to limitations on Platinum UK's operations.

        Platinum UK has applied to the FSA to write the business conducted by St. Paul Re in the United Kingdom. Platinum UK will not be licensed by the FSA at the time of the completion of the Equity Public Offering. The issuance of the license is at the discretion of the FSA and we may not be able to obtain such a license. St. Paul Re has agreed that it will continue to write reinsurance in the United Kingdom, at the direction of Platinum UK, in cases where we are unable to underwrite that business ourselves because, despite using our reasonable best efforts, we have not obtained the necessary regulatory license or approval to do so or we have not yet been approved as a reinsurer by the cedent. We will reinsure all such business, together with certain other business written by St. Paul Re UK since January 1, 2002. If Platinum UK does not obtain a license by the first anniversary of the completion of the Equity Public Offering, or if the license it obtains contains material limitations or if we determine to terminate or significantly reduce our operations in the United Kingdom, our results of operations could be materially adversely affected, and we may not be able to conduct our UK operations in the manner described in this prospectus.

We may not be able to satisfy the conditions to borrowing under our committed credit facility, and failure to do so would limit our liquidity.

        We have entered into a 364 day committed credit facility with a group of banks that will permit us to make borrowings of up to $100 million in the aggregate from time to time. The credit facility contains various covenants and agreements, including a requirement that we satisfy specified tangible net worth and leverage ratios. It is a condition to our ability to borrow under the credit facility that we have received not less than $825 million of aggregate proceeds (net of the underwriters' discount) from the sale of Platinum Holdings' Common Shares in the Equity Public Offering, the RenaissanceRe Investment and the Cash Contribution. Assuming an initial public offering price of $22.00 per Common Share (the low end of the range at which Platinum Holdings proposes to offer the Common Shares in the Equity Public Offering), a Cash Contribution of $121 million and proceeds of $83 million from the RenaissanceRe Investment, and assuming no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering, we expect to receive aggregate net proceeds of approximately $829 million from the Equity Public Offering, the Cash Contribution and the RenaissanceRe Investment. We may not raise net proceeds in such amount, and, if we fail to do so, we will be unable to borrow under the facility. In addition, we may not be able to extend or replace this credit facility on satisfactory terms when it terminates on June 20, 2003. Failure to satisfy the conditions to borrowing under our credit facility, or to extend or replace it when it expires, would limit Platinum Holdings' liquidity to the net proceeds of the Equity Public Offering, the RenaissanceRe Investment and the Cash Contribution retained by it and dividends, if any, received from Platinum US, Platinum UK and Platinum Bermuda unless we arrange for other sources of liquidity.

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We do not yet have in place a letter of credit facility, and failure to arrange for such a facility could affect our ability to compete for certain business.

        We do not yet have in place a letter of credit facility. Many U.S. jurisdictions do not permit insurance companies to take credit for reinsurance obtained from unlicensed or non-admitted insurers on their U.S. statutory financial statements without appropriate security, which can include a letter of credit. Platinum UK and Platinum Bermuda will not be licensed in any U.S. jurisdiction, and Platinum US will not be licensed in certain U.S. jurisdictions. If we fail to obtain a letter of credit, and are unable to otherwise provide the necessary security, insurance companies may be less willing to purchase our reinsurance products than if we had a letter of credit. If this is the case, there may be a material adverse effect on our results of operations. If and when we seek to obtain a letter of credit, we may not be able to obtain one upon terms acceptable to us.

Platinum Holdings is a holding company and, consequently, it is dependent on the payment of cash dividends or the extension of loans by Platinum US, Platinum UK and Platinum Bermuda.

        Platinum Holdings is a holding company that will conduct no reinsurance operations of its own. All operations will be conducted by its wholly owned operating subsidiaries, Platinum US, Platinum UK and Platinum Bermuda. As a holding company, Platinum Holdings' cash flow will consist primarily of dividends, interest and other permissible payments from its subsidiaries. Platinum Holdings will depend on such payments to receive funds for general corporate purposes and to meet its obligations, including the payment of any dividends to its shareholders. Additionally, under the Bermuda Companies Act 1981, Platinum Holdings may declare or pay a dividend only if, among other things, it has reasonable grounds for believing that it is, or would after the payment be, able to pay its liabilities as they become due. For a discussion of the legal limitations on our subsidiaries' ability to pay dividends to Platinum Holdings, see "Management's Discussion and Analysis of Pro Forma Financial Condition and Underwriting Results—Liquidity and Capital Resources—Restrictions on Dividend Payments from Our Operating Subsidiaries" and "Business—Regulation."

The regulatory system under which we operate, and potential changes thereto, could significantly and adversely affect our business.

        Platinum Holdings.    As the indirect parent of Platinum US, Platinum Holdings will be subject to the insurance holding company laws of Maryland, where Platinum US is organized and domiciled. This law generally requires the insurance holding company and each insurance company directly or indirectly owned by the holding company to register with the Maryland Insurance Commissioner and to furnish annually financial and other information. Generally, all transactions affecting the insurers in the holding company system must be fair and, if material, require prior notice and approval or non-disapproval by the Maryland Insurance Commissioner.

        Platinum US.    Platinum US is organized and domiciled in Maryland and licensed, authorized or accredited to write reinsurance in 24 states of the United States and is seeking licenses in eight additional states. State insurance laws regulate many aspects of its reinsurance business and state insurance departments in the licensure states will supervise its reinsurance operations. Its principal insurance regulatory authority will be the Maryland Insurance Commissioner. The purpose of the state insurance regulatory statutes is to protect insureds and ceding insurance companies, not our shareholders. Among other things, Maryland regulation requires Platinum US to maintain minimum levels of capital, surplus and liquidity, and imposes restrictions on payment of dividends and distributions. These statutes and regulations may, in effect, restrict the ability of Platinum US to write new business or, as indicated above, distribute funds to Platinum Holdings. In recent years, the state insurance regulatory framework has come under increased federal scrutiny, and some state legislators have considered or enacted laws that may alter or increase state authority to regulate insurance companies and insurance holding companies. Moreover, the National Association of Insurance Commissioners (NAIC), which is an association of the senior insurance regulatory officials of all 50 states and the District of Columbia, and state insurance regulators regularly reexamine

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existing laws and regulations, interpretations of existing laws and the development of new laws, which may be more restrictive or may result in higher costs to us than current statutory requirements.

         Platinum UK.    As described above, upon completion of the Equity Public Offering, Platinum UK will not be authorized by the FSA to conduct insurance business in the United Kingdom. However, if and when Platinum UK becomes an authorized person, its insurance business will be subject to close supervision by the FSA.

        We expect the FSA will take a rigorous and proactive approach to its supervisory duties. Among other things, the FSA is seeking to strengthen its requirements for senior management arrangements, systems and controls by requiring insurance companies to maintain risk management teams, to determine and document policies for dealing with risks and to demonstrate how combinations of risks have been aggregated and mitigated. In addition, as part of an initiative to integrate regulation throughout the financial services sector, the FSA intends to place an increased emphasis on risk identification and management in relation to the prudential regulation of insurance businesses in the United Kingdom.

        Further, in July 2002, the FSA issued proposals aimed at ensuring adequate diversification of an insurer's or reinsurer's exposures to reinsurers (whether intra- or extra-group). The proposals are currently in draft form. If adopted in their current form, the proposals would limit the extent to which Platinum UK could reinsure business to Platinum Bermuda, and this could adversely affect our earnings. Final rules and guidance based on these proposals are expected to be implemented in 2004. However, substantial compliance with CP143 in its draft form is likely to be an effective condition for receiving FSA authorization. We are seeking consent from the FSA for Platinum Bermuda to reinsure up to approximately 55% of Platinum UK's reinsurance business, excluding business subject to the Quota Share Retrocession Agreements, written after the Equity Public Offering; however, such consent may not be granted. See "Business—Our Business—Regulation—U.K. Regulation—Proposed Limits on Concentration of Reinsurance Exposures."

        In addition, given that the framework for supervision of insurance companies in the United Kingdom is largely formed by European Union ("EU") directives (which are implemented by member states through national legislation), changes at the EU level may affect the regulatory scheme under which Platinum UK operates. A general review of EU insurance directives is currently in progress and may lead to changes such as increased minimum capital requirements.

        Platinum Bermuda.    Platinum Bermuda is a registered Bermuda insurance company and is subject to regulation and supervision in Bermuda. The applicable Bermuda statutes and regulations generally are designed to protect insureds and ceding insurance companies, not our shareholders. Platinum Bermuda is not registered or licensed as an insurance company in any jurisdiction outside Bermuda. Platinum Bermuda will conduct its business through its offices in Bermuda and will not maintain an office, and its personnel will not conduct any insurance activities in the United States or elsewhere. Although Platinum Bermuda does not believe it will be in violation of insurance laws of any jurisdiction outside Bermuda, inquiries or challenges to Platinum Bermuda's insurance activities may still be raised in the future.

        Platinum Bermuda may be at a competitive disadvantage in jurisdictions where it is not licensed, authorized or accredited or does not enjoy an exemption from licensing. Platinum Bermuda may not be able to obtain any additional licenses, authorizations or accreditations or may be able to do so only at great cost. Many U.S. jurisdictions do not permit insurance companies to take credit for reinsurance obtained from unlicensed or non-admitted insurers on their U.S. statutory financial statements without appropriate security. We expect that Platinum Bermuda's reinsurance clients will typically require it to post a letter of credit or enter into other security arrangements, which will increase its costs of operations relative to reinsurers not required to do so. If Platinum Bermuda is unable to obtain a letter of credit facility on commercially acceptable terms or is unable to arrange for other types of security, its ability to operate its business may be severely limited.

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        The offshore insurance and reinsurance regulatory framework recently has become subject to increased scrutiny in many jurisdictions, including in the United States and in various states within the United States. In the past, there have been congressional and other proposals in the United States regarding increased supervision and regulation of the insurance industry, including proposals to supervise and regulate reinsurers domiciled outside the United States. If Platinum Bermuda were to become subject to any insurance laws and regulations of the United States or any U.S. state, which are generally more restrictive than those applicable to it in Bermuda, at any time in the future, it might be required to post deposits or maintain minimum surplus levels and might be prohibited from engaging in lines of business or from writing specified types of policies or contracts. Complying with those laws could have a material adverse effect on our ability to conduct business or our results of operations.

We will be dependent on the business provided to us by reinsurance brokers and we may be exposed to liability for brokers' failure to make payments to clients for their claims.

        We intend to market most of our reinsurance products through reinsurance brokers. The reinsurance brokerage industry generally, and our sources of business specifically, are concentrated. On a pro forma basis, based on net premiums written during the six months ended June 30, 2002, the five brokers from which St. Paul Re derived the largest portions of its business (with the approximate percentage of our business derived from such brokers and their affiliates) are Aon Corporation (25.5%), Marsh & McLennan Companies (20.9%), Benfield Blanch Inc. (19.6%), Willis Group Holdings (9.4%) and Towers Perrin (3.0%). Loss of all or a substantial portion of the business provided by such intermediaries could have a material adverse effect on us. In addition, at least two of these brokers have announced their intention to form new Bermuda reinsurance companies that may compete with us, and these brokers may favor their own reinsurers over other companies, including us.

        In accordance with industry practice, we expect to frequently pay amounts owing in respect of claims under our policies to reinsurance brokers, for payment over to the ceding insurers. In the event that a broker fails to make such a payment, depending on the jurisdiction, we may remain liable to the ceding insurer for the deficiency. Conversely, in certain jurisdictions, when premiums for such policies are paid to reinsurance brokers for payment over to us, such premiums will be deemed to have been paid and the ceding insurer will no longer be liable to us for those amounts whether or not actually received by us. Consequently, we will assume a degree of credit risk associated with our brokers during the payment process.

Because we are dependent on certain contractual relationships with St. Paul, our principal shareholder, we may experience conflicts of interest with St. Paul that may be detrimental to our business.

        Concurrently with the Equity Public Offering, in return for the Cash Contribution and the contribution of the Transferred Business, we have agreed to issue 6,000,000 Common Shares to St. Paul and to grant to St. Paul the St. Paul Option, as described in more detail under "St. Paul Investment, RenaissanceRe Investment and Principal Shareholders." Following the Equity Public Offering and the St. Paul Investment, St. Paul will own 15.0% of our Common Shares (which shares will be limited to 9.9% of the voting power of the outstanding Common Shares), and will be able, through exercise in full of the St. Paul Option, to increase its ownership to approximately 26.1% of our Common Shares, assuming no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares or of the RenaissanceRe Option. St. Paul has agreed with us that, prior to any exercise of the St. Paul Option, it will, if necessary, dispose of a sufficient number of Common Shares so that, immediately after exercise of the St. Paul Option, St. Paul will not be a "United States 25% Shareholder" as defined under "Description of Platinum Holdings' Common Shares—Restrictions on Transfer." St. Paul's interest in owning Common Shares may be different from that of other shareholders.

        In connection with our formation, we have agreed with St. Paul and certain of its affiliates to enter into, among other things, a Formation and Separation Agreement, Master Services

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Agreements, Quota Share Retrocession Agreements, Run-off Services Agreements and Underwriting Management Agreements. These agreements, which we refer to as the "Inception Agreements", will become effective upon the completion of the Equity Public Offering (except the Quota Share Retrocession Agreements which will take effect at 12:01 a.m. on the day immediately following the date of completion of the Equity Public Offering and will govern our relationship with St. Paul with respect to various intercompany services, which we and St. Paul will provide one another following the completion of the Equity Public Offering. The terms of the Inception Agreements have been negotiated between Platinum and St. Paul but do not necessarily reflect terms that Platinum or St. Paul would agree to with an independent third party. Notwithstanding these contractual relationships, St. Paul (other than as restricted by the non-competition provisions of the Formation and Separation Agreement and of the UK Business Transfer Agreement), and its subsidiaries and affiliates, may from time to time compete with us, including by assisting or investing in the formation of other entities engaged in the insurance and reinsurance businesses. Conflicts of interest could also arise with respect to business opportunities that could be advantageous to St. Paul and any of its subsidiaries or affiliates, on the one hand, and us, on the other hand. Other than as specified in the Inception Agreements, St. Paul is under no obligation to deal with us on any basis other than arm's length or to treat us as a "preferred provider" or grant us any other preferential treatment. St. Paul or its subsidiaries or affiliates have entered, and may enter, into agreements and maintain relationships with numerous companies that may directly compete with us.

Risk Factors Relating to the Units

You will bear the entire risk of a decline in the price of the Common Shares.

        The market value of the Common Shares you will purchase on the share purchase date may be materially lower than the price per share that the purchase contract requires you to pay. If the average of the closing price per Common Share over the 20 trading-day period ending on the third trading day immediately preceding the share purchase date is less than $            per share, you will, on the share purchase date, be required to purchase Common Shares at a price per share of $             . Accordingly, a holder of units assumes the entire risk that the market value of the Common Shares may decline and that the decline could be substantial.

You will receive only a portion of any appreciation in the Common Share price.

        The aggregate market value of the Common Shares you will receive upon settlement of a purchase contract generally will exceed the stated amount of $25 only if the average of the closing price per Common Share over the 20 trading-day period ending on the third trading day immediately preceding the share purchase date equals or exceeds $            , which is referred to as the "threshold appreciation price." The threshold appreciation price represents an appreciation of            % over $            . If the applicable average closing price exceeds $            , which is referred to as the "reference price", but falls below the threshold appreciation price, you will realize no equity appreciation on the Common Shares for the period during which you own a unit. Furthermore, if the applicable average closing price exceeds the threshold appreciation price, the value of the Common Shares you will receive under the purchase contract will be approximately      % of the value of the Common Shares you could have purchased with $25 at the time of the ESU Offering. During the period prior to settlement, an investment in the units affords less opportunity for equity appreciation than a direct investment in the Common Shares.

The trading price of the Common Shares and the general level of interest rates and our credit quality will directly affect the trading price for the units.

        It is impossible to predict whether the price of the Common Shares or interest rates will rise or fall. Our operating results and prospects and economic, financial and other factors will affect trading prices of the Common Shares and the units. In addition, market conditions can affect the capital markets generally, thereby affecting the price of the Common Shares. These conditions may include the level of, and fluctuations in, the trading prices of stocks generally and sales of substantial amounts of Common Shares in the market after the Equity Public Offering or the perception that

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those sales could occur. Fluctuations in interest rates may give rise to arbitrage opportunities based upon changes in the relative value of the Common Shares underlying the purchase contracts and of the other components of the units. The arbitrage could, in turn, affect the trading prices of the units.

You may suffer dilution of the Common Shares issuable upon settlement of your purchase contract.

        The number of Common Shares issuable upon settlement of your purchase contract is subject to adjustment only for stock splits and combinations, stock dividends and specified other transactions that significantly modify the capital structure of Platinum Holdings. The number of Common Shares issuable upon settlement of each purchase contract is not subject to adjustment for other events, including employee stock option grants, ordinary dividends, offerings of Common Shares for cash, or in connection with acquisitions or other transactions which may adversely affect the price of the Common Shares. The terms of the units do not restrict the ability of Platinum Holdings to offer Common Shares in the future or to engage in other transactions that could dilute the Common Shares. Platinum Holdings has no obligation to consider the interests of the holders of the units in engaging in any such offering or transaction. If Platinum Holdings issues additional Common Shares, that issuance may materially and adversely affect the price of the Common Shares and, because of the relationship of the number of Common Shares holders are to receive on the share purchase date to the price of the Common Shares, such other events may adversely affect the trading price of the units.

You will have no rights as common shareholders but will be subject to all changes with respect to the Common Shares.

        Until you acquire Common Shares upon settlement of your purchase contract, you will have no rights with respect to the Common Shares, including voting rights, rights to respond to tender offers and rights to receive any dividends or other distributions on the Common Shares. Platinum Holdings intends to declare and pay quarterly cash dividends beginning in the fourth quarter of 2002. Only holders of Common Shares, not holders of units, will receive such dividends. Upon settlement of your purchase contract, you will be entitled to exercise the rights of a holder of Common Shares only as to actions for which the record date occurs after the settlement date.

Your pledged securities will be encumbered.

        Although holders of units will hold beneficial ownership interests in the underlying pledged senior notes or treasury securities, the holders will pledge those securities with the collateral agent to secure their obligations under the related purchase contracts. Therefore, for so long as the purchase contracts remain in effect, holders will not be allowed to withdraw their ownership interest in the pledged senior notes or treasury securities from this pledge arrangement, except upon substitution of other securities as described in this prospectus.

The secondary market for the units may be illiquid.

        We are unable to predict how the units will trade in the secondary market or whether that market will be liquid or illiquid. There is currently no secondary market for the units. Although the normal units have been approved for listing on the New York Stock Exchange, subject to notice of issuance, we have no obligation or current intention to apply for any separate listing of the stripped units or the senior notes on any stock exchange. We can give you no assurance as to the liquidity of any market that may develop for the normal units, the stripped units or the senior notes, your ability to sell such securities or whether a trading market, if it develops, will continue. In addition, in the event that sufficient numbers of normal units are converted to stripped units, the liquidity of normal units could be adversely affected. It is possible that the normal units, and the stripped units or senior notes if they are ever listed, could be delisted from the New York Stock Exchange or that trading in the normal units, stripped units or senior notes could be suspended as a result of elections to create stripped units or recreate normal units through the substitution of collateral that

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causes the number of these securities to fall below the applicable requirements for listing securities on the New York Stock Exchange.

Delivery of the securities under the pledge agreement is subject to potential delay if Platinum Holdings becomes subject to a bankruptcy proceeding.

        Notwithstanding the automatic termination of the purchase contracts, if Platinum Holdings becomes the subject of a case under the federal bankruptcy code, the imposition of an automatic stay under Section 362 of the federal bankruptcy code may delay the delivery to you of your securities being held as collateral under the pledge arrangement and such delay may continue until the automatic stay has been lifted. The automatic stay will not be lifted until such time as the bankruptcy judge agrees to lift it and allows your collateral to be returned to you. Similarly, if Platinum Holdings becomes the subject of winding up proceedings under the Bermuda Companies Act 1981, a delay may result from the automatic stay of proceedings against Platinum Holdings and may continue until the court decides to lift the stay.

Platinum Finance may redeem the senior notes upon the occurrence of a tax event.

        Platinum Finance has the option to redeem the senior notes, on not less than 30 days' nor more than 60 days' prior written notice, in whole but not in part, at any time if a tax event occurs and continues under the circumstances described in this prospectus. See "Description of the Senior Notes—Tax Event Redemption." If Platinum Finance exercises this option, the senior notes will be redeemed at the redemption price (described later in this prospectus) plus accrued and unpaid interest, if any, to the date of redemption. If the senior notes are redeemed, Platinum Finance will pay the redemption price, plus accrued and unpaid interest, if any, to the date of redemption, in cash to the holders of ownership interests in the senior notes. If the tax event redemption occurs prior to the earlier of the share purchase date or a successful remarketing of the senior notes, the redemption price payable to you as a holder of the normal units will be distributed to the collateral agent, who in turn will apply an amount equal to the redemption price to purchase a portfolio of zero-coupon U.S. treasury securities on your behalf, and will remit the remainder of the redemption price, if any, to you, and these treasury securities will be substituted for the senior notes as collateral to secure your obligations under the purchase contracts related to the normal units. If your senior notes are not components of normal units, you, rather than the collateral agent, will receive the related redemption payments. We can give you no assurance as to the effect on the market prices for the normal units if we substitute the treasury securities as collateral in place of any senior notes so redeemed. A tax event redemption will be a taxable event to the holders of the senior notes.

Because Platinum Holdings and Platinum Finance are each holding companies with no operations of their own, Platinum Finance's obligations under the senior notes and Platinum Holdings' obligations under the guarantee and the purchase contracts are effectively subordinated to the debt and other obligations of their respective subsidiaries.

        Both Platinum Holdings and Platinum Finance are holding companies with no operations of their own. Platinum Holdings' ability to pay its obligations under the purchase contracts and the guarantee is dependent upon its ability to obtain cash dividends or other cash payments or loans from its subsidiaries. Similarly, Platinum Finance's ability to pay its obligations under the senior notes is dependent upon its ability to obtain cash dividends or loans from its subsidiaries. Platinum Holdings' and Platinum Finance's operating subsidiaries are separate and distinct legal entities and will have no obligation, contingent or otherwise, to pay any dividends or make any other distributions (except for payments required pursuant to the terms of intercompany indebtedness) to Platinum Holdings or Platinum Finance. Various financing arrangements, charter provisions and regulatory requirements may impose certain restrictions on the abilities of Platinum Holdings' and Platinum Finance's subsidiaries to transfer funds to Platinum Holdings and Platinum Finance in the form of cash dividends, loans or advances. See "Risks Related to Our Business—Platinum Holdings

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is a holding company and, consequently, it is dependent on the payment of cash dividends or the extension of loans by Platinum US, Platinum UK and Platinum Bermuda."

        In addition, because Platinum Holdings and Platinum Finance are holding companies, except to the extent that Platinum Holdings or Platinum Finance has priority or equal claims against its subsidiaries as a creditor, Platinum Finance's obligations under the senior notes and Platinum Holdings' obligations under the guarantee and the purchase contracts will be effectively subordinated to the debt and other obligations of their respective subsidiaries because, as the shareholders of their subsidiaries, they will be subject to the prior claims of creditors of their subsidiaries. As of June 30, 2002, on a pro forma basis, Platinum Finance's subsidiaries had no liabilities or obligations that would have effectively ranked senior to the senior notes and Platinum Holdings' subsidiaries had approximately $270 million in liabilities and obligations that would have effectively ranked senior to the guarantees.

Platinum Holdings may defer contract adjustment payments.

        Platinum Holdings has the option to defer the payment of all or part of the contract adjustment payments on the purchase contracts forming a part of the units until no later than the share purchase date. However, deferred contract adjustment payments will accrue additional contract adjustment payments at the rate of            % per year (compounded quarterly) until paid. If the purchase contracts are terminated due to Platinum Holdings' bankruptcy, insolvency or reorganization, the right to receive contract adjustment payments and deferred contract adjustment payments, if any, will also terminate.

The U.S. federal income tax consequences of the purchase, ownership and disposition of the units are unclear.

        No statutory, judicial or administrative authority directly addresses the treatment of the units or instruments similar to the units for U.S. federal income tax purposes. As a result, the U.S. federal income tax consequences of the purchase, ownership and disposition of the units are not entirely clear. In addition, if the senior notes are (as we believe they should be) treated as contingent payment debt instruments, any gain on the disposition of a senior note prior to the date on which the interest rate on the senior note is reset generally should be treated as ordinary interest income; thus, the ability to offset such interest income with a loss, if any, on a purchase contract may be limited.

Assuming the senior notes are classified as contingent payment debt instruments, you will have to include interest in your taxable income in excess of current cash flows, and gain recognized on your disposition of a senior note will generally be treated as ordinary interest income.

        Because of the manner in which the interest rate on the senior notes is reset, we believe the senior notes should be classified as contingent payment debt instruments subject to the "noncontingent bond method" for accruing original issue discount for United States income tax purposes. Assuming the senior notes are so treated, original issue discount will accrue from the issue date of the senior notes and will be included in your gross income for United States income tax purposes on a constant yield-to-maturity basis, regardless of your usual method of tax accounting, and adjustments will be made to reflect actual payments on the senior notes. For all accrual periods ending on or prior to            , 2005, and possibly thereafter, the original issue discount that accrues on the senior notes will exceed the stated interest payments on the senior notes. In addition, any gain on the disposition of a senior note before the share purchase date will generally be treated as ordinary interest income, and the ability to offset this interest income with a loss, if any, on a purchase contract may be limited.

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The trading price of the senior notes may not fully reflect the value of their accrued but unpaid interest.

        The senior notes may trade at a price that does not fully reflect the value of their accrued but unpaid interest. If you dispose of your senior notes between record dates for interest payments, you will be required to include in gross income the daily portions of original issue discount through the date of disposition as ordinary income, and to add this amount to your adjusted tax basis in the senior notes disposed of. To the extent the selling price is less than your adjusted tax basis, you will recognize a loss. Some or all of this loss may be capital loss. The deductibility of capital losses for U.S. federal income tax purposes is subject to certain limitations.

Risks Related to Our Common Shares

There is no prior public market for the Common Shares.

        Prior to the Equity Public Offering, there has been no public trading market for the Common Shares. If an active trading market does not develop and continue upon completion of the Equity Public Offering, your investment may become less liquid and the market price of the Common Shares may decline, even below the initial public offering price. The initial public offering price per Common Share in the Equity Public Offering will be determined by agreement among the Company, St. Paul and the representatives of the underwriters and may not be indicative of the market price of the Common Shares after the Equity Public Offering. The Common Shares have been approved for listing on the New York Stock Exchange under the symbol "PTP", subject to notice of issuance.

It may be difficult to enforce service of process and enforcement of judgments against us and our officers and directors.

        We are a Bermuda company and certain of our officers and directors will be residents of various jurisdictions outside the United States. A substantial portion of our assets and our officers and directors, at any one time, are or may be located in jurisdictions outside the United States. Although we have irrevocably appointed CT Corporation System as an agent in New York, New York to receive service of process with respect to actions against us arising out of violations of the U.S. federal securities laws in any federal or state court in the United States relating to the transactions covered by this prospectus, it may be difficult for investors to effect service of process within the United States on our directors and officers who reside outside the United States or to enforce against us or our directors and officers judgments of U.S. courts predicated upon civil liability provisions of the U.S. federal securities laws.

Future sales of Common Shares may affect their market price.

        Sales of substantial amounts of the Common Shares in the public market following the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment, or the perception that such sales could occur, could adversely affect the market price of the Common Shares and may make it more difficult for us to sell our equity securities in the future, or for shareholders to sell their Common Shares, at a time and price which they deem appropriate. Upon completion of the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment, there will be 40,000,000 Common Shares outstanding. In the event the underwriters' option to purchase an additional 4,506,000 Common Shares is exercised, St. Paul has the option to purchase (at a price per share equal to the initial public offering price less the underwriting discount) up to an additional 900,000 Common Shares in order to maintain the proportionate initial share ownership in the Company it obtained prior to the underwriters exercising their option to purchase additional Common Shares, and RenaissanceRe has the option to purchase (at a price per share equal to the initial public offering price less the underwriting discount) up to an additional 594,000 Common Shares in order to maintain the proportionate initial share ownership in the Company it obtained prior to the underwriters exercising their option to purchase additional Common Shares. As a result, if the underwriters' option to purchase additional Common Shares is exercised in full and these additional shares are purchased by St. Paul and RenaissanceRe, there would be 46,000,000 Common Shares

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outstanding upon completion of the Equity Public Offering, the St. Paul Investment and the RenaissanceRe Investment. Furthermore, upon the settlement of the purchase contracts forming part of the equity security units on          2005, an additional number of Common Shares, to be determined based upon a settlement rate, will be sold to the holders of the equity security units. In that event, St. Paul and RenaissanceRe may exercise their pre-emptive rights to purchase a corresponding number of Common Shares to maintain their respective proportionate ownership interests in Platinum Holdings.

        The Common Shares sold in the Equity Public Offering and issuable to the holders of equity security units on          , 2005 will be freely tradeable without restriction or future registration under the Securities Act of 1933, as amended (the "1933 Act"), by persons other than "affiliates" of the Company. The Common Shares issued in the St. Paul Investment and the RenaissanceRe Investment, the Common Shares issuable pursuant to the St. Paul Option and the RenaissanceRe Option, and the Common Shares St. Paul and RenaissanceRe may purchase pursuant to their pre-emptive rights upon the settlement of the purchase contracts forming part of the equity security units will be "restricted securities" within the meaning of the 1933 Act and may not be sold in the absence of registration under the 1933 Act or an exemption therefrom. St. Paul and RenaissanceRe have been granted rights to require Platinum Holdings to register Common Shares they own. Platinum Holdings, its officers and directors, Platinum Finance, St. Paul and RenaissanceRe have agreed with the underwriters not to offer, sell, contract to sell, pledge, grant any option to purchase, hedge, make any short sale or otherwise dispose of any Common Shares or equity security units (including the related purchase contracts and senior notes), or any securities of the Company that are substantially similar to Common Shares or equity security units (including the related purchase contracts or senior notes), or any securities of Platinum Finance that are substantially similar to the senior notes, or any options or warrants to purchase any of Common Shares or equity security units (including the related purchase contracts and senior notes), or any securities convertible into, exchangeable for or that represent the right to receive Common Shares or equity security units (including the related purchase contracts and senior notes) (and, with respect to the Company, other than the initial issuance of Common Shares to be offered and sold concurrently with this offering and the securities to be offered and sold in the St. Paul Investment and the RenaissanceRe Investment) during the period from the date of this prospectus continuing to and including the date 180 days after the date of this prospectus, except with the prior written consent of Goldman, Sachs & Co., Merrill Lynch, Pierce, Fenner & Smith Incorporated and Salomon Smith Barney Inc. and subject to other specified exceptions. See "Shares Eligible for Future Sale" for a discussion of certain transfer restrictions. RenaissanceRe has agreed with us that for a period of one year from the closing date of the Equity Public Offering it will not sell, offer to sell, contract to sell or otherwise dispose of any Common Shares or any other securities convertible into or exercisable or exchangeable for any Common Shares or grant options to purchase any Common Shares, subject to certain limited exceptions. For a description of the St. Paul Investment and the RenaissanceRe Investment, see "St. Paul Investment, RenaissanceRe Investment and Principal Shareholders." For a description of St. Paul's pre-emptive rights, see "Certain Relationships and Related Transactions—The St. Paul Investment—Formation and Separation Agreement—Pre-Emptive Rights." For a description of RenaissanceRe's pre-emptive rights, see "Certain Relationships and Related Transactions—The RenaissanceRe Investment—Transfer Restrictions, Registration Rights and Standstill Agreement—Pre-Emptive Rights."

There are limitations on the ownership, transfer and voting rights of our Common Shares.

        Under our bye-laws, our directors are required to decline to register any transfer of Common Shares that would result in a person (or any group of which such person is a member) beneficially owning, directly or indirectly, 10% or more of the voting shares, or in the case of St. Paul and its subsidiaries, or RenaissanceRe and its subsidiaries, beneficially owning, directly or indirectly, 25% or more of such shares or of the total combined value of our issued shares. Similar restrictions apply to our ability to issue or repurchase shares. These restrictions on the transfer, issuance or repurchase of shares do not apply to any issuance of shares to a person (other than St. Paul and

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its subsidiaries and RenaissanceRe and its subsidiaries) pursuant to a contract to purchase Common Shares from Platinum Holdings included in the equity security units. The directors also may, in their discretion, decline to register the transfer of any shares if they have reason to believe (1) that the transfer may lead to adverse tax or regulatory consequences in any jurisdiction or (2) that the transfer would violate the registration requirements of the U.S. federal securities laws or of any other jurisdiction. These restrictions would apply to a transfer of shares even if the transfer has been executed on the New York Stock Exchange. A transferor of Common Shares will be deemed to own those shares for dividend, voting and reporting purposes until a transfer of those Common Shares has been registered on our register of shareholders. We are authorized to request information from any holder or prospective acquiror of Common Shares as necessary to give effect to the transfer, issuance and repurchase restrictions referred to above, and may decline to effect any transaction if complete and accurate information is not received as requested.

        In addition, our bye-laws generally provide that any person (or any group of which such person is a member) beneficially owning, directly or indirectly, shares carrying 10% or more of the total voting rights attached to all of our outstanding voting shares will have the voting rights attached to its issued shares reduced so that it may not exercise 10% or more of such total voting rights. Because of the attribution provisions of the U.S. Internal Revenue Code of 1986, as amended (the "Code"), and the rules of the Securities and Exchange Commission (the "SEC") regarding determination of beneficial ownership, this requirement may have the effect of reducing the voting rights of a shareholder whether or not such shareholder directly holds 10% or more of our Common Shares. Further, the directors have the authority to require from any shareholder certain information for the purpose of determining whether that shareholder's voting rights are to be reduced. Failure to respond to such a notice, or submitting incomplete or inaccurate information, gives the directors (or their designee) discretion to disregard all votes attached to that shareholder's Common Shares. See "Description of Platinum Holdings' Common Shares."

        The insurance law of Maryland prevents any person from acquiring control of us or of Platinum US unless that person has filed a notification with specified information with the Maryland Insurance Commissioner and has obtained his prior approval. Under the Maryland statute, acquiring 10% or more of the voting stock of an insurance company or its parent company is presumptively considered a change in control, although such presumption may be rebutted. Accordingly, any person who acquires, directly or indirectly, 10% or more of the voting securities of Platinum Holdings without the prior approval of the Maryland Insurance Commissioner will be in violation of this law and may be subject to injunctive action requiring the disposition or seizure of those securities by the Maryland Insurance Commissioner or prohibiting the voting of those securities and to other actions determined by the Maryland Insurance Commissioner. In addition, many U.S. state insurance laws require prior notification of state insurance departments of a change in control of a non-domiciliary insurance company doing business in that state. While these pre-notification statutes do not authorize the state insurance departments to disapprove the change in control, they authorize regulatory action in the affected state if particular conditions exist such as undue market concentration. Any future transactions that would constitute a change in control of Platinum Holdings may require prior notification in those states that have adopted preacquisition notification laws.

        Common Shares may be offered or sold in Bermuda only in compliance with the provisions of the Investment Business Act 1998 of Bermuda. In addition, sales of Common Shares to persons resident in Bermuda for Bermuda exchange control purposes may require the prior approval of the Bermuda Monetary Authority. Consent under the Exchange Act of 1972 (and regulations thereunder) has been obtained from the Bermuda Monetary Authority for the issue and transfer of the Common Shares being offered pursuant to this offering and between non-residents of Bermuda for exchange control purposes, provided our Common Shares remain listed on an appointed stock exchange, which includes the New York Stock Exchange. This prospectus will be filed with the Registrar of Companies in Bermuda in accordance with Bermuda law. In giving such consent, and in accepting this prospectus for filing, neither the Bermuda Monetary Authority nor the Registrar of

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Companies accepts any responsibility for the financial soundness of any proposal or for the correctness of any of the statements made or opinions expressed herein.

        The Financial Services and Markets Act 2000 ("FSMA") regulates the acquisition of "control" of any U.K. insurance company authorized under FSMA. Any company or individual that (together with its or his associates) directly or indirectly acquires 10% or more of the shares in the parent company of a U.K. authorized insurance company, or is entitled to exercise or control the exercise of 10% or more of the voting power in such a parent company, would be considered to have acquired "control" for the purposes of the relevant legislation, as would a person who had significant influence over the management of such parent company by virtue of his shareholding in it. A purchaser of more than 10% of the Common Shares would therefore be considered to have acquired "control" of Platinum UK.

        Under FSMA, any person proposing to acquire "control" over a U.K. authorized insurance company must give prior notification to the FSA of his intention to do so. The FSA would then have three months to consider that person's application to acquire "control." In considering whether to approve such application, the FSA must be satisfied both that the acquirer is a fit and proper person to have such "control" and that the interests of consumers would not be threatened by such acquisition of "control." Failure to make the relevant prior application would constitute a criminal offense.

        The foregoing provisions of our bye-laws and legal restrictions will have the effect of rendering more difficult or discouraging unsolicited takeover bids from third parties or the removal of incumbent management.

Your investment could be materially adversely affected if we are deemed to be engaged in business in the United States.

        Platinum Holdings and Platinum Bermuda are Bermuda companies, Platinum UK is a U.K. company, and Platinum Ireland is an Irish company. We believe that Platinum Holdings, Platinum UK, Platinum Bermuda and Platinum Ireland will each operate in such a manner that none of these companies will be subject to U.S. tax (other than U.S. excise tax on reinsurance premiums and withholding tax on certain investment income from U.S. sources) because they will not be engaged in a trade or business in the United States. Nevertheless, because definitive identification of activities which constitute being engaged in a trade or business in the United States is not provided by the Code or regulations or court decisions, the U.S. Internal Revenue Service (the "IRS") might contend that any of Platinum Holdings, Platinum UK, Platinum Bermuda or Platinum Ireland are/is engaged in a trade or business in the United States. If Platinum Holdings, Platinum UK, Platinum Bermuda or Platinum Ireland were engaged in a trade or business in the United States, and if Platinum UK, Platinum Bermuda or Platinum Ireland were to qualify for benefits under the applicable income tax treaty with the United States, but such trade or business were attributable to a "permanent establishment" in the United States (or, in the case of Platinum Bermuda, with respect to investment income, arguably even if such income were not attributable to a "permanent establishment"), Platinum Holdings, Platinum UK, Platinum Bermuda and/or Platinum Ireland would be subject to U.S. tax at regular corporate rates on the income that is effectively connected with the U.S. trade or business, plus an additional 30% "branch profits" tax on such income remaining after the regular tax in certain circumstances, in which case our earnings and your investment could be materially adversely affected.

If you acquire 10% or more of the Common Shares, CFC rules may apply to you.

Under the Code, each "United States shareholder" of a foreign corporation that is a "controlled foreign corporation" ("CFC") for an uninterrupted period of 30 days or more during a taxable year, and who owns shares in the CFC on the last day of the CFC's taxable year, must include in its gross income for U.S. federal income tax purposes its pro rata share of the CFC's "subpart F income", even if the subpart F income is not distributed. For these purposes, any U.S. person who owns, directly or indirectly through a foreign entity or through the constructive ownership rules of the Code, 10% or more of the total combined voting power of all classes of stock of a foreign corporation will

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be considered to be a "United States shareholder." In general, a foreign insurance company such as Platinum UK or Platinum Bermuda is treated as a CFC only if such "United States shareholders" collectively own more than 25% of the total combined voting power or total value of our stock. St. Paul will actually own approximately 15% (and will, after applying the constructive ownership rules of the Code, own no more than 24.9%) of the Common Shares upon completion of the Equity Public Offering, assuming no exercise of the underwriters' option to purchase additional Common Shares, although, pursuant to our bye-laws, the combined voting power of these shares is limited to approximately 9.9% of the combined voting power of all Common Shares. We expect that, because of the limitations on concentration of voting power of our Common Shares, the dispersion of our share ownership among holders other than St. Paul, the provisions for directed voting on matters requiring action by the shareholders of Platinum Bermuda, Platinum Ireland and Platinum UK (including the election of the members of their boards of directors) and the restrictions on transfer, issuance or repurchase of the Common Shares, you will not be subject to treatment as a "United States shareholder" of a CFC. In addition, because under our bye-laws no single shareholder (including St. Paul) is permitted to exercise, after taking into account Common Shares constructively owned or held indirectly through a foreign entity, as much as 10% of the total combined voting power of the Company, you should not be viewed as a "United States shareholder" of a CFC for purposes of these rules. However, these rules could apply to you. Accordingly, U.S. persons who might, directly, or indirectly through a foreign entity or through the constructive ownership rules of the Code, acquire or be deemed to acquire 10% or more of our Common Shares should consider the possible application of the CFC rules.

Under certain circumstances, you may be required to pay taxes on your pro rata share of Platinum Bermuda's and Platinum UK's related person insurance income.

        If Platinum UK's or Platinum Bermuda's related person insurance income ("RPII") were to equal or exceed 20% of Platinum UK's or Platinum Bermuda's gross insurance income in any taxable year and direct or indirect insureds (and persons related to such insureds) own (or are treated as owning directly or indirectly) 20% or more of the voting power or value of the shares of Platinum UK or Platinum Bermuda, a U.S. person who owns the Common Shares of Platinum Holdings directly or indirectly on the last day of the taxable year would be required to include in its income for U.S. federal income tax purposes the shareholder's pro rata share of Platinum UK's or Platinum Bermuda's RPII for the entire taxable year, determined as if such RPII were distributed proportionately to such United States shareholders at that date regardless of whether such income is distributed. In addition, U.S. tax-exempt organizations would be required to treat RPII as unrelated business taxable income if Platinum UK's or Platinum Bermuda's RPII equaled or exceeded 20% of Platinum UK's or Platinum Bermuda's gross insurance income in any taxable year. The amount of RPII earned by Platinum UK or Platinum Bermuda (generally, premium and related investment income from the direct or indirect insurance or reinsurance of any direct or indirect U.S. shareholder of Platinum UK or Platinum Bermuda or any person related to such shareholder, including St. Paul) will depend on a number of factors, including the geographic distribution of Platinum UK's or Platinum Bermuda's business and the identity of persons directly or indirectly insured or reinsured by Platinum UK or Platinum Bermuda. Some of the factors which determine the extent of RPII in any period may be beyond Platinum UK's or Platinum Bermuda's control. Consequently, Platinum UK's or Platinum Bermuda's RPII could equal or exceed 20% of its gross insurance income in any taxable year and ownership of its shares by direct or indirect insureds and related persons could equal or exceed the 20% threshold described above.

        The RPII rules provide that if a shareholder who is a U.S. person disposes of shares in a foreign insurance corporation that has RPII (even if the amount of RPII is less than 20% of the corporation's gross insurance income) and in which U.S. persons own 25% or more of the shares, any gain from the disposition will generally be treated as ordinary income to the extent of the shareholder's share of the corporation's undistributed earnings and profits that were accumulated during the period that the shareholder owned the shares (whether or not such earnings and profits are attributable to RPII). In addition, such a shareholder will be required to comply with certain

52

reporting requirements, regardless of the amount of shares owned by the shareholder. These rules should not apply to dispositions of Common Shares because Platinum Holdings will not itself be directly engaged in the insurance business and because proposed U.S. Treasury regulations appear to apply only in the case of shares of corporations that are directly engaged in the insurance business. However, the IRS might interpret the proposed regulations in a different manner and the applicable proposed regulations may be promulgated in final form in a manner that would cause these rules to apply to dispositions of our Common Shares.

Changes in U.S. federal income tax law could materially adversely affect shareholders' investment.

        Recently proposed U.S. legislation targeting so-called "inversion transactions" would under certain circumstances treat a foreign corporation as a U.S. corporation for U.S. federal income tax purposes and under other circumstances would require obtaining IRS approval of the terms of related-party transactions. In addition, interest deductions on debt borrowed from or guaranteed by a related non-U.S. party would be more severely limited than under existing so-called "earnings stripping" provisions.

        The Company and its subsidiaries would appear generally not to be subject to the proposed legislation directed at inversion transactions as currently drafted. However, the proposed changes to the earnings stripping provisions could impose significant restrictions on the amount of interest deductible by the Company's U.S. subsidiaries on certain debt owed to or guaranteed by related non-U.S. parties (including the surplus note to be issued by Platinum US to Platinum Ireland and the senior notes to be issued by Platinum Finance and guaranteed by the Company). We cannot predict whether the proposed legislation (or any similar legislation) will be enacted or, if enacted, what the specific provisions or the effective date of any such legislation would be, or whether it would have any effect on the Company or its subsidiaries.

        If the inversion legislation were enacted and made applicable to the Company and its subsidiaries, we could be treated as a U.S. corporation. If we were treated as a U.S. corporation, we would be subject to taxation in the United States at regular corporate rates, in which case our earnings and shareholders' investments would be materially adversely affected. In addition, the U.S. tax consequences to our shareholders would be significantly different from those described below in "U.S. Federal Income Tax Consequences—Common Shares." If the inversion legislation were to so apply, however, the earnings stripping provisions would, if also enacted, be inapplicable to the extent the non-U.S. related-party lender or guarantor was treated as a U.S. corporation under the inversion legislation. Prospective investors should consult their own tax advisors regarding the U.S. tax consequences to them, in their particular circumstances, if we were treated as a U.S. corporation.

        In addition, a bill has been introduced in the House of Representatives that would effectively deny—by deferring for an extended period—a U.S.-based insurer or reinsurer that reinsures or retrocedes a portion of its risk with or to a related foreign-based reinsurer or retrocedent in a low tax rate jurisdiction (such as Bermuda) a deduction for the portion of the insurance or reinsurance premium ceded to the related foreign-based party, thereby effectively subjecting all of the premium income to U.S. tax. Moreover, a senior official of the U.S. Treasury Department has also identified related party reinsurance arrangements as an area that requires study because it may result in an inappropriate shift of income from a U.S. corporate group to its foreign affiliates, implying that, were that to be the conclusion of such a study, legislation, possibly in the form of legislation imposing a premium-based tax, might be needed. Enactment of legislation of either type could materially adversely affect our earnings and shareholders' investments.

We may become subject to taxes in Bermuda after 2016.

        We have received a standard assurance from the Bermuda Minister of Finance, under Bermuda's Exempted Undertakings Tax Protection Act 1966, that if any legislation is enacted in Bermuda that would impose tax computed on profits or income, or computed on any capital asset, gain or appreciation, or any tax in the nature of estate duty or inheritance tax, then the imposition of

53

any such tax will not be applicable to us or to any of our operations or our shares, debentures or other obligations until March 28, 2016. Consequently, if our Bermuda tax exemption is not extended past March 28, 2016, we may be subject to any Bermuda tax after that date. For more information on Bermuda taxation of Platinum Holdings and Platinum Bermuda, see "U.S. Federal Income Tax Consequences."

Bermuda could be subject to sanctions by a number of multinational organizations which could adversely affect Bermuda companies.

        A number of multinational organizations, including the EU, the Organization for Economic Cooperation and Development ("OECD"), including its Financial Action Task Force, and the Financial Stability Forum have all recently identified certain countries as blocking information exchange, engaging in harmful tax competition or not maintaining adequate controls to prevent corruption, such as money laundering activities. Recommendations to limit such harmful practices are under consideration by these organizations, and a recent report published on November 27, 2001 by the OECD contains an extensive discussion of specific recommendations. The OECD has threatened non-member jurisdictions that do not agree to cooperate with the OECD with punitive sanctions by OECD member countries. It is unclear what these sanctions will be and if they will be imposed. Bermuda has committed to a course of action to enable compliance with the requirements of these multinational organizations. However, the action taken by Bermuda may not be sufficient to preclude all effects of the measures or sanctions described above, which if ultimately adopted could adversely affect Bermuda companies such as Platinum Holdings and Platinum Bermuda.

        Some of the statements contained in this prospectus, including those using words such as "believes", "expects", "intends", "estimates", "projects", "predicts", "assumes", "anticipates", "plans" and "seeks", and variations thereof, are forward-looking statements. Forward-looking statements are statements other than of historical fact. Since Platinum has no history of operations, most of the statements relating to Platinum and its business, including statements relating to its competitive strengths and business strategies, are forward-looking statements. These forward-looking statements are subject to risks and uncertainties and are not a guarantee of future performance. In light of these risks and uncertainties, actual results may differ materially from those suggested by the forward-looking statements for various reasons, including those discussed in this section. We may not be able to conduct our business successfully, execute our strategies effectively or achieve our financial and other objectives.

        As with any equity-related investment, the price of the equity security units may fluctuate widely depending on many factors, including:

•

the perceived prospects of our business in particular and the insurance, asset management, securities and financial services industries generally;

•

differences between our actual financial and operating results and those expected by investors and analysts;

•

changes in analysts' recommendations or projections;

•

changes in general economic, market and political conditions; and

•

broad market and interest rate fluctuations.

54

USE OF PROCEEDS

        Assuming no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering or the underwriters' option to purchase additional equity security units, we expect to receive net proceeds (after the underwriters' discount and before expenses) from the Equity Public Offering, the Cash Contribution, the RenaissanceRe Investment and the ESU Offering as set forth in the following table:

(1)

Components may not add to totals due to rounding.

        Assuming full exercise (which is in their sole discretion) by the underwriters, St. Paul and RenaissanceRe of their options to purchase additional Common Shares in connection with the Equity Public Offering and the underwriters' option to purchase additional equity security units, we expect to receive net proceeds (after the underwriters' discount and before expenses) from the Equity Public Offering, the Cash Contribution, the RenaissanceRe Investment and the ESU Offering as set forth in the following table:

        A portion of the net proceeds of the Equity Public Offering, the Cash Contribution and the RenaissanceRe Investment, currently estimated at approximately $10 million, will be retained by Platinum Holdings and the balance will be contributed to the capital of Platinum US (in an amount not less than $250 million, which includes net proceeds from the ESU Offering as discussed below), Platinum UK (in an amount not less than $150 million, upon its being licensed in the United Kingdom), Platinum Ireland (in an amount not less than $100 million, substantially all of which will be used to purchase a surplus note issued by Platinum US) and Platinum Bermuda (in an amount not less than $375 million). To the extent we receive net proceeds from the Equity Public Offering, the Cash Contribution and the RenaissanceRe Investment in excess of the minimum amounts stated above, we expect to contribute substantially all such proceeds to the capital of Platinum Bermuda. All but approximately $20 million of the net proceeds from the ESU Offering (or approximately $23 million if the underwriters exercise in full their option to purchase additional equity security units) will be contributed to Platinum US. The remaining net proceeds from the ESU Offering will be retained by Platinum Finance.

        The allocation of net proceeds among our three operating subsidiaries (Platinum US, Platinum UK and Platinum Bermuda) and Platinum Ireland has been determined based on: our assessment of the level of capital that is prudent to support their expected levels of reinsurance business; applicable regulatory requirements; discussions with insurance regulatory authorities and rating

55

agencies; and capital efficiency considerations. The amount of net proceeds to be retained by Platinum Finance will be sufficient for it to pay three years of interest on the senior notes that it will issue in the ESU Offering while the net proceeds to be retained by Platinum Holdings is the amount that management believes to be appropriate given its expected initial cash needs.

        The following table shows the application of the minimum and maximum aggregate estimated net proceeds of the Equity Public Offering, the Cash Contribution, the RenaissanceRe Investment and the ESU Offering. The minimum net proceeds assume an initial public offering price of $22.00 per Common Share and no exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering or the underwriters' option to purchase additional equity security units (i.e., aggregate net proceeds of $949 million) and the maximum net proceeds assume an initial public offering price of $23.00 per share and full exercise of the underwriters', St. Paul's and RenaissanceRe's options to purchase additional Common Shares in connection with the Equity Public Offering and the underwriters' option to purchase additional equity security units (i.e., aggregate net proceeds of $1,136 million):

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DILUTION

        If you purchase units in this offering and hold them on the share purchase date, you will acquire Common Shares on that date and may experience dilution of your investment in Platinum Holdings. Net tangible book value per Common Share represents the amount of tangible assets less total liabilities, divided by the number of Common Shares outstanding. Dilution in net tangible book value per Common Share represents the difference between the amount per Common Share that you will pay on the share purchase date, if you purchase units in this offering and hold them on that date, for Common Shares of Platinum Holdings and the net tangible book value per Common Share, immediately after the Equity Public Offering but giving effect to our sale of the Common Shares pursuant to the purchase contracts included in the units. Since we cannot predict the net tangible book value the Common Shares will have when you purchase them on the share purchase date, we present here pro forma calculations of the dilution that would occur if the net tangible book value of the Common Shares on that date were the same as it would have been on June 30, 2002 had all the transactions referred to below occurred on that date. In addition, since the number and price of Common Shares to be purchased pursuant to the purchase contract included in each unit, or settlement rate, depends on the market value of the Common Shares prior to the share purchase date, we present these pro forma calculations for the minimum and maximum prices per Common Share to be purchased pursuant to the purchase contracts.

        As described under "Description of the Equity Security Units—Description of the Purchase Contracts", the settlement rate will be $25, which is the stated amount per equity security unit, divided by (a) the reference price if the applicable market value is less than or equal to the reference price, (b) the applicable market value if the applicable market value is less than the threshold appreciation price but greater than the reference price, or (c) the threshold appreciation price if the applicable market value is equal to or greater than the threshold appreciation price. The applicable market value means the average of the closing price per Common Share on each of the 20 consecutive trading days ending on the third trading day immediately prior to the share purchase date. For purposes of this presentation, we assume that the reference price will equal the price per Common Share in the Equity Public Offering and that the threshold appreciation price will equal      % of the reference price.

        Because St. Paul will make the Cash Contribution and contribute the Transferred Business, having a net tangible book value of approximately $11 million as of June 30, 2002, to Platinum Holdings in return for its Common Shares and the St. Paul Option, and because Platinum Holdings will record the assets so contributed at their net book value, and because RenaissanceRe will pay a purchase price per share equal to the initial public offering price less the underwriting discount in the RenaissanceRe Investment, the initial public offering price per Common Share in the Equity Public Offering, as well as the price per Common Share which holders of the units will pay on the share purchase date, are higher than Platinum Holdings' pro forma net tangible book value per share as of June 30, 2002.

        St. Paul's Cash Contribution ranging from $121 million to $126 million and its contribution of the Transferred Business in return for 6,000,000 Common Shares and the St. Paul Option, Platinum Holdings' sale of 30,040,000 Common Shares in the Equity Public Offering at an initial public offering price of between $22.00 and $23.00 per Common Share, the RenaissanceRe Investment ranging from $83 million to $86 million and Platinum Holdings' sale of $125 million stated amount of equity security units in this offering, after deduction of underwriting discounts and commissions and estimated formation, organization and offering expenses payable by us, will result in net proceeds to us of approximately $949 million to $987 million. Assuming an initial public offering price of $22.50 per Common Share (the midpoint of the range at which Platinum Holdings proposes to offer these shares) and giving immediate effect to Platinum Holdings' sale of the Common Shares pursuant to the share purchase contracts included in the units, Platinum Holdings'

57

pro forma net tangible book value as of June 30, 2002 would have been approximately $     million, or, depending on the settlement rate of the units, between $         and $        per Common Share. Depending on the settlement rate of the units and based on the assumptions outlined above, this represents an immediate dilution in pro forma net tangible book value of approximately $                        to $                    per equity security unit to purchasers in this offering.

As Platinum Holdings is newly formed, its net tangible book value before the Equity Public Offering, this offering, the St. Paul Investment and the RenaissanceRe Investment was $120,000 as of June 30, 2002.

        The following tables set forth, on a pro forma basis as of June 30, 2002, and assuming an initial public offering price of $22.50 per Common Share (the mid-point of the range at which Platinum Holdings proposes to offer the Common Shares), for St. Paul, RenaissanceRe and the investors in the Equity Public Offering and the ESU Offering and that the applicable market value is as indicated:

•

the number of Common Shares purchased from us;

•

the total consideration paid (including cash, and in the case of St. Paul, the outstanding capital stock of Platinum US, which includes net assets of approximately $5 million in cash and cash equivalents after reflecting a dividend of $15 million to be paid, prior to the completion of the Equity Public Offering, to United States Fidelity and Guaranty Company, the current parent of Platinum US);

•

the average price per Common Share paid by St. Paul and RenaissanceRe, which represents an amount approximately equal to the initial public offering price of the Common Shares less the underwriters' discount; and

•

the average price per Common Share paid by investors in the Equity Public Offering and the ESU Offering before deducting underwriting discounts and commissions and estimated offering expenses.

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Applicable Market Value less than or equal to $22.50 per Share

Applicable Market Value equal to or greater than $        per Share

        The above tables do not include St. Paul's contribution to Platinum of tangible assets and certain intangible assets having a net book value of approximately $7 million as of June 30, 2002. The above tables also do not include Common Shares issuable upon (1) exercise of the underwriters' option to purchase additional Common Shares in the Equity Public Offering and the concurrent optional purchase by St. Paul or RenaissanceRe of additional Common Shares to maintain their respective proportionate share ownership immediately following the Equity Public Offering, (2) exercise of the St. Paul Option, (3) exercise of the RenaissanceRe Option, (4) exercise of options to be issued to our management and other employees pursuant to our employee compensation plans or (5) settlement of the purchase contracts contained in the equity security units, if any, issued upon exercise of the underwriters' option to purchase additional equity security units in this offering. Assuming an initial public offering price of from $22.00 to $23.00, respectively, St. Paul's contribution would be for an average price of from $21.98 to $22.93 per share, and RenaissanceRe's contribution would be for an average price of from $20.85 to $21.79 per share.

        Assuming that the threshhold appreciation price of the equity security units is not greater than 120% of the reference price, any exercise of the St. Paul Option or the RenaissanceRe Option would not be dilutive to investors in this offering because the exercise price for each of the options is 120% of the initial public offering price of the Common Shares, which will be equal to the reference price. We have estimated the fair value of the St. Paul Option (to St. Paul) to be between approximately $42 million and $66 million, and the fair value of the RenaissanceRe Option (to RenaissanceRe) to be between approximately $18 million and $28 million, or between approximately $7.00 and $11.00 per underlying Common Share for each of St. Paul and RenaissanceRe as of the date of this preliminary prospectus, assuming the initial public offering price is $22.50 per Common Share. Such estimates were determined using the Black-Scholes model for valuing options, and incorporated the following assumptions: ten-year holding period; stock volatility of between 30% and 45%; ten-year discount and loan rate of approximately 4.4%; and a dividend rate of $0.32 per year.

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DIVIDEND POLICY

        We intend to recommend that our Board of Directors authorize the payment of a dividend of $0.32 for 2003. It is intended that dividends will be recommended to the Board for approval and payment on a quarterly basis. The declaration and payment of dividends will be at the discretion of the Board of Directors of Platinum Holdings but will be prohibited if certain contract adjustment payments in respect of the equity security units are deferred, and will depend upon our results of operations and cash flows, the financial position and capital requirements of Platinum US, Platinum UK and Platinum Bermuda, general business conditions, legal, tax and regulatory restrictions on the payment of dividends and other factors the Board of Directors of Platinum Holdings deems relevant. While the Company is not itself subject to any significant legal prohibitions on the payment of dividends, Platinum US will be subject to regulatory constraints imposed by Maryland insurance law, Platinum UK will be subject to regulatory constraints imposed by U.K. insurance law, Platinum Ireland will be subject to constraints imposed by Irish law, and Platinum Bermuda will be subject to regulatory constraints imposed by Bermuda insurance law, which affect their ability to pay dividends to the Company. See "Business—Our Business—Regulation." Accordingly, there is no requirement or assurance that dividends will be declared or paid in the future. In addition, we do not expect that our rate of dividend increase, if any, will be more than 10% per year, and we have agreed to adjust the exercise price in the St. Paul Option and the RenaissanceRe Option to the extent dividend increases exceed such rate. See "Certain Relationships and Related Transactions—The St. Paul Investment—St. Paul Option Agreement" and "—The RenaissanceRe Investment—RenaissanceRe Option Agreement."

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CAPITALIZATION

        The following table sets forth the capitalization of the Company as of June 30, 2002 and as adjusted to give effect to the Equity Public Offering and the RenaissanceRe Investment based on an assumed initial public offering price in the Equity Public Offering of $22.50 per Common Share (the midpoint of the range at which Platinum Holdings proposes to offer the Common Shares) and a Cash Contribution of $123 million (the midpoint of the $121 million to $126 million range for the Cash Contribution), as well as the ESU Offering. This table assumes no exercise by the underwriters, St. Paul or RenaissanceRe of their options to purchase up to, in aggregate, 6,000,000 additional Common Shares in connection with the Equity Public Offering or the underwriters' option to purchase up to $18.75 million of additional equity security units in the ESU Offering.

(1)

Reflects an adjustment representing the present value of the contract adjustment payments payable in connection with the purchase contracts contained in the equity security units.

(2)

Reflects certain formation and organization expenses as discussed in Notes 2 and 12 to our consolidated balance sheet on pages F-5 and F-13 of this prospectus.

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RATIO OF EARNINGS TO FIXED CHARGES

        The following table sets forth Platinum Holdings' ratio of earnings to fixed charges for the years and the period indicated:

(1)

For the period from April 24, 2002 (date of inception of Platinum Holdings) through June 30, 2002, Platinum Holdings did not generate earnings or fixed charges, and therefore a ratio of earnings to fixed charges is not meaningful. For the years 1997 to 2001, St. Paul Re was the predecessor to Platinum Holdings. Since a complete income statement does not exist for St. Paul Re for those years, a ratio of earnings to fixed charges is not meaningful.

        Earnings consist of income from continuing operations before income taxes plus fixed charges, net of capitalized interest. Fixed charges consist of interest expense before reduction for capitalized interest and one-third of rental expense, which is considered to be representative of an interest factor.

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PRO FORMA FINANCIAL INFORMATION

        We caution that the Platinum pro forma consolidated balance sheet and pro forma combined underwriting results presented herein are not indicative of the actual results that we expect to achieve once we commence operations. Many factors may cause our actual results to differ materially from the pro forma consolidated balance sheet and underwriting results including, but not limited to, the following:

•

Platinum's pro forma combined statement of underwriting results includes premium and loss development on business entered into prior to January 1, 2002. Under the Quota Share Retrocession Agreements, we are assuming no premium or loss development on business entered into prior to January 1, 2002. Therefore, our reported premiums written and earned and reported losses and loss adjustment expenses in our initial years of operation could be substantially lower than as presented in Platinum's pro forma combined statement of underwriting results. As such, our reported results in our initial years of operation will not be subject to prior year development for periods prior to January 1, 2002.



•

Following the Equity Public Offering, we will report underwriting results under the Quota Share Retrocession Agreements for the period through the date of completion of the Equity Public Offering based on the application of retroactive reinsurance accounting, resulting in the premiums earned and losses incurred by St. Paul during such period being excluded from our statement of underwriting results. Due to this exclusion, following the Equity Public Offering, our reported 2002 premiums written and earned and our net underwriting results in 2002 could be substantially different than as presented in Platinum's pro forma combined statement of underwriting results.



•

Platinum's pro forma consolidated balance sheet reflects the inception of the Quota Share Retrocession Agreements assuming transferred balances as of June 30, 2002. Platinum's actual consolidated balance sheet will report transferred amounts determined as of 12:01 a.m. on the day immediately following the date of completion of the Equity Public Offering. Accordingly, underwriting gain or loss with respect to the Assumed Reinsurance Contracts for the period from January 1, 2002 through such date will be retained by St. Paul.



•

Although we expect to continue to be afforded the benefits of most of St. Paul Re's retrocessional reinsurance program through their expiration during 2002, we may enter into retrocessional reinsurance contracts with significantly different terms and conditions from those that have been made available to us from St. Paul Re and which form the basis of our initial operations.



•

The additional and reinstatement premiums recorded in 2001 by St. Paul Re's Finite Risk operating segment were primarily caused by losses relating to the September 11, 2001 terrorist attack. These additional and reinstatement premiums were unusually high and not necessarily indicative of the recurring premium volume we expect to write in that business segment.



•

Platinum's pro forma financial statements continue to reflect the discounting of the liability for certain Assumed Reinsurance Contracts based on our current intention to make arrangements to permit such discounting. If we do not put such arrangements in place, reinsurance contracts of a similar type entered into in the future would be reported on an undiscounted basis.

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Pro Forma Consolidated Balance Sheet

        We have prepared our unaudited pro forma consolidated balance sheet as of June 30, 2002 to reflect our initial capitalization in the amount of $120,000 and adjusted to reflect, among other things:

•

amounts reflecting (a) the receipt of approximately $725 million, representing the estimated net proceeds from the Equity Public Offering and the RenaissanceRe Investment based on an assumed initial public offering price of $22.50 per Common Share (the midpoint of the range at which Platinum Holdings proposes to offer the Common Shares), without giving effect to any exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares, (b) the redemption of the Common Shares that were issued at inception and capital contributed prior to the Equity Public Offering, (c) the payment of certain formation and organization expenses, as discussed in Note 2 and Note 12 to our consolidated balance sheet on pages F-5 and F-13 of this prospectus, which total $5.1 million, of which $2.1 million has been expensed as of June 30, 2002, and (d) our entering into, and accruing for, the Services and Capacity Reservation Agreement as of June 30, 2002. Additional formation and organization expenses will be incurred prior to closing. It is further assumed that the net proceeds from the Equity Public Offering will be invested in long-term, taxable fixed income securities;



•

amounts representing the receipt of St. Paul's Cash Contribution of $123 million (the mid-point of the $121 million to $126 million range for the Cash Contribution) and the contribution of the Transferred Business at historical cost in exchange for the issuance of Common Shares and the St. Paul Option. Amounts related to net tangible assets contributed to Platinum by St. Paul are recorded at St. Paul's book value as of June 30, 2002. Assets as of June 30, 2002 include approximately $5 million of net assets of Platinum US consisting of cash and cash equivalents (which reflect a dividend of $15 million to be paid, prior to the completion of the Equity Public Offering, to United States Fidelity and Guaranty Company, the current parent of Platinum US) as well as approximately $7 million of tangible assets and other intangible assets such as broker and customer lists and contract renewal rights and licenses;



•

amounts reflecting the receipt of approximately $120 million, representing the estimated net proceeds from the ESU Offering and recognition of the present value of future contract adjustment payments payable on the purchase contracts contained within the equity security units, without giving effect to any exercise of the underwriters' option to purchase additional equity security units. It is further assumed that the net proceeds from the ESU Offering will be invested in long-term, taxable fixed income securities; and



•

amounts reflecting Platinum entering into the Quota Share Retrocession Agreements with St. Paul Re reinsuring the Assumed Reinsurance Contracts as of June 30, 2002.

64

Notes to Pro Forma Consolidated Balance Sheet

The following describe amounts included in the "Adjustments" columns above:

1.

Amounts reflecting (a) the receipt of approximately $725 million, representing the estimated net proceeds from the Equity Public Offering and the RenaissanceRe Investment based on an assumed initial public offering price of $22.50 per Common Share (the midpoint of the range at which Platinum Holdings proposes to offer the Common Shares), without giving effect to any exercise of the underwriters', St. Paul's or RenaissanceRe's options to purchase additional Common Shares, (b) the redemption of the Common Shares that were issued at inception and capital contributed prior to the Equity Public Offering, (c) the payment of certain formation and organization expenses as discussed in Note 2 and Note 12 on pages F-5 and F-13 of this prospectus, which total $5.1 million, of which $2.1 million has been expensed as of June 30, 2002, and (d) our entering into, and accruing for, the Services and Capacity Reservation Agreement as of June 30, 2002. Additional formation and organization expenses will be incurred prior to closing. It is further assumed that the net proceeds from the Equity Public Offering will be invested in long-term, taxable fixed income securities.

2.

Amounts representing the receipt of St. Paul's Cash Contribution of $123 million (the mid-point of the $121 million to $126 million range for the Cash Contribution) and the contribution of the Transferred Business at historical cost in exchange for the issuance of Common Shares and the St. Paul Option. Amounts related to net tangible assets contributed to Platinum by St. Paul are recorded at St. Paul's book value as of June 30, 2002. Assets as of June 30, 2002 include approximately $5 million of net assets of Platinum US consisting of cash and cash equivalents (which reflect a dividend of $15 million to be paid, prior to the completion of the Equity Public Offering, to United States Fidelity and Guaranty Company, the current parent of Platinum US) as well as approximately $7 million of tangible assets and other intangible assets such as broker and customer lists and contract renewal rights and licenses.

3.

Amounts reflecting the receipt of approximately $120 million, representing the estimated net proceeds from the ESU Offering and recognition of the present value of future contract adjustment payments payable on the purchase contracts contained within the equity security units, without giving effect to any exercise of the underwriters' option to purchase additional

65

equity security units. It is further assumed that the net proceeds from the ESU Offering will be invested in long-term, taxable fixed income securities.

4.

Amounts reflecting Platinum entering into the Quota Share Retrocession Agreements with St. Paul Re reinsuring the Assumed Reinsurance Contracts as of June 30, 2002.

Pro Forma Combined Statements of Underwriting Results for the Six Months Ended June 30, 2002 and 2001, and the Year Ended December 31, 2001

        We have prepared our unaudited pro forma combined statements of underwriting results to represent our reinsurance business, as if we had commenced our operations and the Equity Public Offering, the ESU Offering, the St. Paul Investment and the RenaissanceRe Investment had been completed as of January 1, 2001. Our presentation of our pro forma underwriting results assumes that all of the Inception Agreements were entered into as of January 1, 2001. We have based our presentation on St. Paul Re's actual underwriting results for the periods presented. We have then adjusted these historical results to remove any of St. Paul Re's reinsurance businesses that will not be part of Platinum following the completion of the Equity Public Offering, including:

•

amounts related to St. Paul Re's reinsurance business representing lines of business that will not be transferred to Platinum, including aviation and bond and credit reinsurance, certain financial risk and capital markets reinsurance products, and certain North American business previously underwritten in London. Platinum will not obtain the renewal rights to these lines of business and will not assume liabilities related to these lines of business, and Platinum's management does not intend to write these lines of business in the future; and



•

amounts related to St. Paul Re's allocations from the St. Paul corporate aggregate excess-of-loss reinsurance program that will not be available to Platinum.

Except as noted above, the pro forma combined underwriting results assume that all other retrocessional reinsurance with respect to the Assumed Reinsurance Contracts entered into in 2002 will remain available to Platinum.

        Also, as noted above, we have based our pro forma underwriting results on the assumption that all of the Inception Agreements were entered into on January 1, 2001, including the Services and Capacity Reservation Agreement.

        Our future results will depend in part on the amount of our investment income, which cannot be predicted and which will fluctuate depending upon the types of investments we select, our underwriting results and market factors. Actual tax expense in future periods will be based on underwriting results plus investment income and other income and expense items not reflected in the pro forma combined statements of underwriting results. Our effective tax rate will reflect the proportion of income recognized by our operating subsidiaries, with Platinum US taxed at the U.S. corporate income tax rate (35%), Platinum UK taxed at the U.K. corporate tax rate (generally 30%), Platinum Ireland taxed at a 25% corporate tax rate on non-trading income and a 16% corporate tax rate on trading income (the latter rate to be reduced to 12.5% as of January 1, 2003), and Platinum Bermuda taxed at a zero corporate tax rate. In 2002, we expect to have a greater portion of our income subject to U.S. taxation and U.K. taxation than we expect to have in the future because our Bermuda operations are entirely new but can be expected to grow as a proportion of our business. As a result of changes in our geographic distribution of taxable income as well as changes in the

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amount of our non-taxable income and expense, the relationship between our reported income before tax and our income tax expense may change significantly from one period to the next.

Year Ended December 31, 2001