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SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

FOR ANNUAL AND TRANSITION REPORTS

PURSUANT TO SECTIONS 13 OR 15(d) OF THE

SECURITIES ACT OF 1934

For the fiscal year ended December 31, 2003

OR

For the transition period from              to             

Commission file number 1-13087

BOSTON PROPERTIES, INC.

(Exact name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: (617) 236-3300

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of Registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  ¨

Indicate by check mark whether the registrant is an accelerated filer (as defined in Exchange Act Rule 12b-2.    Yes  x    No  ¨

As of June 30, 2003, the aggregate market value of the 92,320,160 shares of common stock held by non-affiliates of the Registrant was $4,043,623,008 based upon the last reported sale price of $43.80 per share on the New York Stock Exchange on such date. (For this computation, the Registrant has excluded the market value of all shares of Common Stock reported as beneficially owned by executive officers and directors of the Registrant; such exclusion shall not be deemed to constitute an admission that any such person is an affiliate of the Registrant.)

As of February 18, 2004, there were 99,636,024 shares of Common Stock outstanding.

Certain information contained in the Registrant’s Proxy Statement relating to its Annual Meeting of Stockholders to be held May 5, 2004 are incorporated by reference in Part III, Items 10, 11, 12, 13 and 14.

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PART I

General

As used herein, the terms “we,” “us,” “our” or the “Company” refer to Boston Properties, Inc., a Delaware corporation organized in 1997, individually or together with its subsidiaries, including Boston Properties Limited Partnership, a Delaware limited partnership, and our predecessors. We are a fully integrated self-administered and self-managed real estate investment trust, or “REIT,” and one of the largest owners and developers of office properties in the United States. Our properties are concentrated in four core markets—Boston, Washington, D.C., midtown Manhattan and San Francisco. We conduct substantially all of our business through our subsidiary Boston Properties Limited Partnership. At December 31, 2003, we owned or had interests in 140 properties, totaling approximately 43.9 million net rentable square feet. Our properties consisted of:

In addition, we own or control 43 parcels of land totaling 551.3 acres and structured parking for 31,098 vehicles containing approximately 9.4 million square feet. Subsequent to December 31, 2003, we sold one industrial property and ten office/technical properties, which consisted of a combined net rentable square feet of 222,081. We consider Class A office properties to be centrally-located buildings that are professionally managed and maintained, attract high-quality tenants and command upper-tier rental rates, and that are modern structures or have been modernized to compete with newer buildings. The Company considers Office/Technical properties to be properties that support office, research and development and other technical uses. Our definition of Class A office and Office/Technical properties may be different than that of other companies.

We are a full-service real estate company, with substantial in-house expertise and resources in acquisitions, development, financing, capital markets, construction management, property management, marketing, leasing, accounting, tax and legal services. As of December 31, 2003, we had approximately 662 employees. Our 28 senior officers have an average of 24 years experience in the real estate industry and an average of 15 years tenure with us. Our principal executive office is located at 111 Huntington Avenue, Boston, Massachusetts 02199 and its telephone number is (617) 236-3300. In addition, we have regional offices at 401 9^th Street, NW, Washington, D.C. 20004; 599 Lexington Avenue, New York, New York 10022; Four Embarcadero Center, San Francisco, California 94111; and 302 Carnegie Center, Princeton, New Jersey 08540.

Our Web site is located at http://www.bostonproperties.com. On our Web site, you can obtain a copy of our annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, as soon as reasonably practicable after we electronically file such material with, or furnish it to, the Securities and Exchange Commission (the “SEC”). The name “Boston Properties” and our logo (consisting of a stylized “b”) are registered service marks of the Company.

Boston Properties Limited Partnership

Boston Properties Limited Partnership, a Delaware limited partnership, is the entity through which we conduct substantially all of our business and own, either directly or through subsidiaries, substantially all of our assets. We are the sole general partner and, as of February 18, 2004, the owner of approximately 77.1% of the economic interests in Boston Properties Limited Partnership. Economic interest was calculated as the number of

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common partnership units of Boston Properties Limited Partnership owned by the Company as a percentage of the sum of (1) the actual aggregate number of outstanding common partnership units of Boston Properties Limited Partnership and (2) the number of common partnership units issuable upon conversion of outstanding preferred partnership units of Boston Properties Limited Partnership. Our general and limited partnership interests in Boston Properties Limited Partnership entitle us to share in cash distributions from, and in the profits and losses of, Boston Properties Limited Partnership in proportion to our percentage interest and entitle us to vote on all matters requiring a vote of the limited partners. Certain other partners of Boston Properties Limited Partnership are persons who contributed their direct or indirect interests in properties to Boston Properties Limited Partnership in exchange for common units or preferred units of limited partnership interest in Boston Properties Limited Partnership. Under the limited partnership agreement of Boston Properties Limited Partnership, unitholders may present their common units of Boston Properties Limited Partnership for redemption at any time (subject to restrictions agreed upon at the time of issuance of the units that may restrict such right for a period of time, generally one year from issuance). Upon presentation of a unit for redemption, BPLP must redeem the unit for cash equal to the then value of a share of our common stock. In lieu of a cash redemption we may elect to acquire any common units so tendered by issuing common stock in exchange for the common units. If we so elect, our common stock will be exchanged for common units on a one-for-one basis. This one-for-one exchange ratio is subject to specified adjustments to prevent dilution. We currently anticipate that we will elect to issue our common stock in connection with each such presentation for redemption rather than having Boston Properties Limited Partnership pay cash. With each such exchange or redemption, our percentage ownership in Boston Properties Limited Partnership will increase. In addition, whenever we issue shares of our common stock other than to acquire common units of Boston Properties Limited Partnership, we must contribute any net proceeds we receive to Boston Properties Limited Partnership and Boston Properties Limited Partnership must issue to us an equivalent number of common units of Boston Properties Limited Partnership. This structure is commonly referred to as an umbrella partnership REIT or “UPREIT.”

Preferred units of Boston Properties Limited Partnership have the rights, preferences and other privileges, including the right to convert into common units of Boston Properties Limited Partnership, as are set forth in amendments to the limited partnership agreement of Boston Properties Limited Partnership. As of December 31, 2003 and February 18, 2004, Boston Properties Limited Partnership had one series of its preferred units outstanding. The Series Two preferred units have an aggregate liquidation preference of approximately $270.0 million. The Series Two preferred units are convertible, at the holder’s election, into common units at a conversion price of $38.10 per common unit (equivalent to a ratio of 1.312336 common units per Series Two preferred unit). Distributions on the Series Two Preferred units are payable quarterly and, unless the higher rate described in the next sentence applies, accrue at 7.0% until May 12, 2009 and 6.0% thereafter. If distributions on the number of common units into which the Series Two Preferred units are convertible are greater than distributions calculated using the rates described in the preceding sentence for the applicable quarterly period, then the greater distributions are payable instead. To date, with the exception of two quarterly distributions on August 15, 2001 and November 15, 2001, distributions have always been made at the fixed rate, rather than the higher rate determined on the basis of distributions paid on the common units into which the Series Two preferred units are convertible. The terms of the Series Two units provide that they may be redeemed for cash in six annual tranches, beginning on May 12, 2009, at our election or at the election of the holders. We also have the right to convert into common units of Boston Properties Limited Partnership any Series Two preferred units that are not redeemed when they are eligible for redemption.

Significant Transactions During 2003

Real Estate Acquisitions/Dispositions

On November 7, 2003, we entered into a binding contract for the sale of Sugarland Business Park—Building Two, an office/technical property totaling approximately 59,000 square feet located in Herndon, Virginia for $7.1 million. The sale closed on February 10, 2004.

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On October 8, 2003, we acquired 1333 New Hampshire Avenue, an approximately 315,000 square foot Class A office property in Washington, D.C. at a purchase price of approximately $111.6 million. The acquisition was financed with borrowings under our unsecured revolving credit facility and available cash. The property is 100% leased.

On September 11, 2003, we entered into a joint venture with an unaffiliated third party to pursue the development of a Class A office property at 801 New Jersey Avenue in Washington, D.C. that, if completed as currently planned, will support approximately 1.1 million square feet of commercial development. We made an initial cash contribution of $3.0 million for a 50% interest in the joint venture.

On August 5, 2003, we acquired three parcels of land totaling approximately 5.8 acres in Reston, Virginia for $13.5 million. If completed as currently planned, the site will support approximately 507,000 square feet of commercial development.

On August 5, 2003, we acquired the remaining outside interests in the One Freedom Square and Two Freedom Square joint venture properties, which together comprise approximately 832,000 square feet of Class A office buildings in Reston, Virginia. The acquisition was financed with $36.0 million of cash and the assumption of the outside partner’s share of the mortgage debt on the properties of approximately $56.4 million and $35.4 million, respectively. Subsequent to the acquisition, we repaid in full the mortgage debt on the Two Freedom Square property totaling $70.7 million.

On April 1, 2003, we acquired the remaining outside interests in the One and Two Discovery Square joint venture properties, which together comprise approximately 367,000 square feet of Class A office buildings in Reston, Virginia. The acquisition was financed with $18.3 million of cash and the assumption of the outside partner’s share of the mortgage debt on the property of approximately $32.4 million. Subsequent to the acquisition, we repaid in full the mortgage debt on the property totaling $64.7 million.

On March 18, 2003, we sold 2300 N Street in Washington, D.C., a Class A office property totaling approximately 289,000 square feet, for net proceeds of approximately $111.5 million, resulting in a gain on sale of approximately $52.7 million (net of minority interest of $11.6 million).

On February 4, 2003, we sold 875 Third Avenue in midtown Manhattan, New York, a Class A office property totaling approximately 712,000 square feet, for net proceeds of approximately $348.9 million, resulting in a gain on sale of approximately $73.6 million (net of minority interest of $16.6 million).

On January 28, 2003, we sold The Candler Building in Baltimore, Maryland, a Class A office property totaling approximately 541,000 square feet, for net proceeds of approximately $61.9 million, resulting in a loss on sale of approximately $0.3 million.

The sales mentioned above of 875 Third Avenue, The Candler Building and 2300 N Street were structured as like-kind exchanges. Accordingly, taxable gain for federal income tax purposes was not recognized and the tax attributes (including depreciated tax basis and any tax protection covenants for the benefit of former owners) of these disposed properties have been transferred to 399 Park Avenue as the property for which they were exchanged.

Developments

We placed two Class A office properties and one retail property in-service during 2003, which required a total investment during 2003 of approximately $10.7 million, of which $3.6 million was funded through construction loans. Our total investment, including equity and debt, through December 31, 2003 on these properties was $139.3 million. We continued construction on an additional three office properties, including one property in which we have a joint venture interest, and incurred approximately $192.2 million of construction

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costs during 2003, of which $155.0 million was funded through existing construction loans and the remainder of which was funded using borrowings under our unsecured line of credit and available cash.

Unsecured Debt

On January 17, 2003, Boston Properties Limited Partnership closed an unregistered offering of $175.0 million in aggregate principal amount of its 6.25% senior unsecured notes due 2013. The notes are fungible, and form a single series, with the $750.0 million of notes sold in December 2002. The notes were offered only to qualified institutional buyers in reliance on Rule 144A under the Securities Act of 1933, as amended. The notes were priced at 99.763% of their face amount to yield 6.28%. We used the net proceeds to repay our unsecured bridge loan, a portion of our unsecured line of credit as well as certain construction loans.

On March 18, 2003, Boston Properties Limited Partnership closed an unregistered offering of $300.0 million in aggregate principal amount of its 5.625% senior unsecured notes due April 15, 2015. The notes were offered only to qualified institutional buyers in reliance on Rule 144A under the Securities Act of 1933, as amended. The notes were priced at 99.898% of their face amount to yield 5.636%. We used the net proceeds to refinance the mortgage debt on Five Times Square and for other general business purposes.

On May 22, 2003, Boston Properties Limited Partnership closed an unregistered offering of $250.0 million in aggregate principal amount of its 5.00% senior unsecured notes due June 1, 2015. The notes were offered only to qualified institutional buyers in reliance on Rule 144A under the Securities Act of 1933, as amended. The notes were priced at 99.329% of their face amount to yield 5.075%. We used the net proceeds to repay the mortgage loan secured by the property at 2600 Tower Oaks Boulevard in Rockville, Maryland totaling $31.0 million, to repay amounts then outstanding under our unsecured revolving credit facility described below and for other general business purposes.

Our unsecured senior notes are redeemable at our option, in whole or in part, at a redemption price equal to the greater of (i) 100% of their principal amount or (ii) the sum of the present value of the remaining scheduled payments of principal and interest discounted at a rate equal to the yield on U.S. Treasury securities with a comparable maturity plus 0.35%, in each case plus accrued and unpaid interest to the redemption date. The indenture under which our senior unsecured notes were issued contains restrictions on incurring debt and using our assets as security in other financing transactions that result in the non-compliance with certain customary financial covenants, including (1) a leverage ratio not to exceed 60%, (2) a secured debt leverage ratio not to exceed 50%, (3) an interest coverage ratio of greater than 1.5, and (4) unencumbered asset value of greater than 150% of our unsecured debt. As of December 31, 2003, we were in compliance with each of these financial restrictions and requirements.

Under registration rights agreements with the initial purchasers of our senior unsecured notes, we agreed to use our reasonable best efforts to register with the SEC offers to exchange new notes issued by us, which we refer to as “exchange notes,” for the original notes. We closed the exchange offers relating to the 6.25% senior unsecured notes due January 15, 2013 on June 20, 2003, and we closed the exchange offer relating to the 5.625% senior unsecured notes due April 15, 2015 and 5.00% senior unsecured notes due June 1, 2015 on September 9, 2003. The exchange notes are in the same aggregate principal amount as and have terms substantially identical to the original notes, but the exchange notes are freely tradable by the holders, while the original notes were subject to resale restrictions. The exchange offers did not generate any cash proceeds for us.

As of February 18, 2004, Boston Properties Limited Partnership had investment grade ratings on its senior unsecured notes, as follows:

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The security rating is not a recommendation to buy, sell or hold securities, as it may be subject to revision or withdrawal at any time by the rating organization. Each rating should be evaluated independently of any other rating.

Equity Transactions

On August 12, 2003, Boston Properties Limited Partnership completed the redemption of all of its Series One Preferred units by converting the remaining 2,365,301 Series One preferred units into 2,102,480 common units of limited partnership interest.

During the year ended December 31, 2003, we issued 2,452,791 shares of common stock as a result of stock options being exercised.

Business and Growth Strategies

Business Strategy

Our primary business objective is to maximize return on investment so as to provide our investors with the greatest possible total return. Our strategy to achieve this objective is:

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Growth Strategies

External Growth

We believe that we are well-positioned to realize growth through external asset development and acquisitions. We believe that our development experience and our organizational depth position us to continue to selectively develop a range of property types, from single-story suburban office properties to high-rise urban developments, within budget and on schedule. Other factors that contribute to our competitive position include:

We have targeted three areas of development and acquisition as significant opportunities to execute our external growth strategy:

In the past, we have been particularly successful at acquiring sites or options to purchase sites that need governmental approvals. Because of our development expertise, knowledge of the governmental approval process and reputation for quality development with local government regulatory bodies, we generally have been able to secure the permits necessary to allow development and to profit from the resulting increase in land value. We seek out complex projects where we can add value through the efforts of our experienced and skilled management team leading to attractive enhanced returns on investment.

Our strong regional relationships and recognized development expertise have enabled us to capitalize on unique build-to-suit opportunities. We intend to seek and expect to continue to be presented with such opportunities in the near term allowing us to earn relatively significant returns on these development opportunities though multiple business cycles.

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Internal Growth

We believe that significant opportunities will exist in the long term to increase cash flow from our existing properties because they are of high quality and in desirable locations. In addition, our properties are in markets where, in general, the creation of new supply is limited by the lack of available sites, the difficulty of receiving the necessary approvals for development on vacant land and the difficulty of obtaining financing. Our strategy for maximizing the benefits from these opportunities is two-fold: (1) to provide high quality property management services using our employees in order to encourage tenants to renew, expand and relocate in our properties, and (2) to achieve speed and transaction cost efficiency in replacing departing tenants through the use of in-house services for marketing, lease negotiation, and construction of tenant improvements. We believe that once the current economic conditions improve, our office properties will add to our internal growth because of their desirable locations. In addition, we believe that once the current economic conditions improve in the business and leisure travel sector, our hotel properties will add to our internal growth because of their desirable locations in the downtown Boston and East Cambridge submarkets. We expect to continue our internal growth as a result of our ability to:

We had an average lease term of 7.0 years at December 31, 2003 and continue to cultivate long-term leasing relationships with a diverse base of high quality, financially stable tenants. Based on leases in place at December 31, 2003, leases with respect to 6.7% of the total square feet from our Class A office properties will expire in calendar year 2004.

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Policies with Respect to Certain Activities

The discussion below sets forth certain additional information regarding our investment, financing and other policies. These policies have been determined by our Board of Directors and, in general, may be amended or revised from time to time by our Board of Directors.

Investment Policies

Investments in Real Estate or Interests in Real Estate

Our investment objectives are to provide quarterly cash dividends to our securityholders and to achieve long-term capital appreciation through increases in the value of Boston Properties, Inc. We have not established a specific policy regarding the relative priority of these investment objectives.

We expect to continue to pursue our investment objectives primarily through the ownership of our current properties and other acquired properties. We currently intend to continue to invest primarily in developments of properties and acquisitions of existing improved properties or properties in need of redevelopment, and acquisitions of land that we believe have development potential, primarily in our four core markets—Boston, Washington, D.C., midtown Manhattan and San Francisco. Future investment or development activities will not be limited to a specified percentage of our assets. We intend to engage in such future investment or development activities in a manner that is consistent with the maintenance of our status as a REIT for federal income tax purposes. In addition, we may purchase or lease income-producing commercial and other types of properties for long-term investment, expand and improve the real estate presently owned or other properties purchased, or sell such real estate properties, in whole or in part, when circumstances warrant. We do not have a policy that restricts the amount or percentage of assets that will be invested in any specific property, however, our investments may be restricted by our debt covenants.

We may also continue to participate with third parties in property ownership, through joint ventures or other types of co-ownership. These investments may permit us to own interests in larger assets without unduly restricting diversification and, therefore, add flexibility in structuring our portfolio.

Equity investments may be subject to existing mortgage financing and other indebtedness or such financing or indebtedness as may be incurred in connection with acquiring or refinancing these investments. Debt service on such financing or indebtedness will have a priority over any distributions with respect to our common stock. Investments are also subject to our policy and therefore, not to be treated as an investment company under the Investment Company Act of 1940, as amended (the “1940 Act”).

Investments in Real Estate Mortgages

While our current portfolio consists of, and our business objectives emphasize, equity investments in commercial real estate, we may, at the discretion of the Board of Directors, invest in mortgages and other types

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of real estate interests consistent with our qualification as a REIT. We do not presently intend to invest in mortgages or deeds of trust, but may invest in participating or convertible mortgages if we conclude that we may benefit from the cash flow or any appreciation in value of the property. Investments in real estate mortgages run the risk that one or more borrowers may default under such mortgages and that the collateral securing such mortgages may not be sufficient to enable us to recoup its full investment.

Securities of or Interests in Persons Primarily Engaged in Real Estate Activities

Subject to the percentage of ownership limitations and gross income tests necessary for our REIT qualification, we also may invest in securities of other REITs, other entities engaged in real estate activities or securities of other issuers, including for the purpose of exercising control over such entities.

Dispositions

Our disposition of properties is based upon management’s periodic review of our portfolio and the determination by the Board of Directors that such action would be in our best interests. Any decision to dispose of a property will be made by our management and approved by a majority of the Board of Directors or a committee there of. Some holders of limited partnership interests in Boston Properties Limited Partnership, including Messrs. Mortimer B. Zuckerman and Edward H. Linde, would incur adverse tax consequences upon the sale of certain of our properties that differ from the tax consequences to us. Consequently holders of limited partnership interests in Boston Properties Limited Partnership may have different objectives regarding the appropriate pricing and timing of any such sale. Such different tax treatment derives in most cases from the fact that we acquired these properties in exchange for partnership interests in contribution transactions structured to allow the prior owners to defer taxable gain. Generally such deferral continues so long as we do not dispose of the properties in a taxable transaction. Unless a sale by us of these properties is structured as a like-kind exchange or in a manner that otherwise allows such deferral to continue, recognition of the deferred tax gain allocable to these prior owners is generally triggered by the sale.

Financing Policies

We do not have a policy limiting the amount of indebtedness that we may incur. However, our mortgages, credit facilities and unsecured debt securities contain customary restrictions, requirements and other limitations on our ability to incur indebtedness. In addition, the agreement of limited partnership of Boston Properties Limited Partnership and our Certificate of Incorporation and Bylaws do not limit the amount or percentage of indebtedness that we may incur. We have not established any limit on the number or amount of mortgages that may be placed on any single property or on our portfolio as a whole.

Our Board of Directors will consider a number of factors when evaluating our level of indebtedness and when making decisions regarding the incurrence of indebtedness, including the purchase price of properties to be acquired with debt financing, the estimated market value of our properties upon refinancing and the ability of particular properties and Boston Properties Limited Partnership as a whole to generate cash flow to cover expected debt service.

Policies with Respect to Other Activities

As the sole general partner of Boston Properties Limited Partnership, we have the authority to issue additional common and preferred units of limited partnership interests of Boston Properties Limited Partnership. We have in the past, and may continue in the future, to issue common or preferred units of limited partnership interests of Boston Properties Limited Partnership to persons who contribute their direct or indirect interests in properties to us in exchange for such common or preferred units of limited partnership interest in Boston Properties Limited Partnership. We have not engaged in trading, underwriting or agency distribution or sale of securities of issuers other than Boston Properties Limited Partnership and we do not intend to do so. At all times,

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we intend to make investments in such a manner as to maintain our qualification as a REIT, unless because of circumstances or changes in the Internal Revenue Code of 1986, as amended (or the Treasury Regulations), our Board of Directors determines that it is no longer in our best interest to qualify as a REIT. We may make loans to third parties, including, without limitation, to joint ventures in which we participate. We intend to make investments in such a way that we will not be treated as an investment company under the 1940 Act. Our policies with respect to these and other activities may be reviewed and modified or amended from time to time by the Board of Directors.

Competition

We compete in the leasing of office and industrial space with a considerable number of other real estate companies, some of which may have greater marketing and financial resources than are available to us. In addition, our hotel properties compete for guests with other hotels, some of which may have greater marketing and financial resources than are available to us and to the manager of our hotels, Marriott ^® International, Inc.

Principal factors of competition in our primary business of, owning, acquiring and developing office properties, are the quality of properties, leasing terms (including rent and other charges and allowances for tenant improvements), attractiveness and convenience of location, the quality and breadth of tenant services provided, and reputation as an owner and operator of quality office properties in the relevant market. Additionally, our ability to compete depends upon, among other factors, trends of the national and local economies, investment alternatives, financial condition and operating results of current and prospective tenants, availability and cost of capital, construction and renovation costs, taxes, governmental regulations, legislation and population trends.

The Hotel Properties

We own our three hotel properties through a taxable REIT subsidiary (“TRS”). The TRS, a wholly-owned subsidiary of Boston Properties Limited Partnership, is the lessee pursuant to leases for each of the hotel properties. As lessor, Boston Properties Limited Partnership is entitled to a percentage of gross receipts from the hotel properties. The hotel leases allow all the economic benefits of ownership to flow to us. Marriott^® International, Inc. continues to manage the hotel properties under the Marriott^® name and under terms of the existing management agreements. Marriott has been engaged under separate long-term incentive management agreements to operate and manage each of the hotels on behalf of the TRS. In connection with these arrangements, Marriott has agreed to operate and maintain the hotels in accordance with its system-wide standard for comparable hotels and to provide the hotels with the benefits of its central reservation system and other chain-wide programs and services. Under a separate management agreement for each hotel, Marriott acts as the TRS’ agent to supervise, direct and control the management and operation of the hotel and receives as compensation base management fees that are calculated as a percentage of the hotel’s gross revenues, and supplemental incentive fees if the hotel exceeds negotiated profitability breakpoints. In addition, the TRS compensates Marriott, on the basis of a formula applied to the hotel’s gross revenues, for certain system-wide services provided by Marriott, including central reservations, marketing and training. During 2003 and 2002, Marriott received an aggregate of approximately $3.4 million and $5.5 million, respectively, under all three management agreements.

Seasonality

Our hotel properties traditionally have experienced significant seasonality in their operating income, with weighted-average net operating income by quarter over the year ended December 31, 2003 as follows:

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Corporate Governance

Since May 2003, we have implemented the following corporate governance initiatives to address certain legal requirements promulgated under the Sarbanes-Oxley Act of 2002, as well as the recently adopted New York Stock Exchange corporate governance listing standards:

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RISK FACTORS

Set forth below are the risks that we believe are material to our investors. We refer to the shares of our common stock and the units of limited partnership interest in Boston Properties Limited Partnership together as our “securities,” and the investors who own shares and/or units as our “securityholders.” This section contains forward-looking statements. You should refer to the explanation of the qualifications and limitations on forward-looking statements beginning on page 34.

Our performance and value are subject to risks associated with our real estate assets and with the real estate industry.

Our economic performance and the value of our real estate assets, and consequently the value of our securities, are subject to the risk that if our office, industrial, and hotel properties do not generate revenues sufficient to meet our operating expenses, including debt service and capital expenditures, our cash flow and ability to pay distributions to our securityholders will be adversely affected. The following factors, among others, may adversely affect the income generated by our office, industrial and hotel properties:

We are dependent upon the economic climates of our four core markets—Boston, Washington, D.C., midtown Manhattan and San Francisco.

Over 90% of our revenues in fiscal year 2003 were derived from properties located in our four core markets: Boston, Washington, D.C., midtown Manhattan and San Francisco. As a result of the continued slowdown in economic activity, there has been an increase in vacancy rates for office properties in these markets compared with historical vacancy rates. A continued downturn in the economies of these markets, or the impact that the downturn in the overall national economy may have upon these economies, could result in further reduced demand for office space. Because our portfolio consists primarily of office buildings (as compared to a more diversified real estate portfolio), a decrease in demand for office space in turn could adversely affect our results of operations. Additionally, there are submarkets within our core markets that are dependent upon a limited number of industries. For example in our Washington, D.C. market, we are primarily dependent on leasing office properties to governmental agencies and legal firms, in our midtown Manhattan market we have historically leased properties to financial, legal and other professional firms and in our suburban Boston submarket we have historically leased office buildings to companies in the technology sector. A significant downturn in one or more of these sectors could adversely affect our results of operations.

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Our investment in property development may be more costly than anticipated.

We intend to continue to develop and substantially renovate office, industrial and hotel properties. Our current and future development and construction activities may be exposed to the following risks:

Investment returns from our developed properties may be lower than anticipated.

Our developed properties may be exposed to the following risks:

Our use of joint ventures may limit our flexibility with jointly owned investments.

In appropriate circumstances, we intend to develop and acquire properties in joint ventures with other persons or entities when circumstances warrant the use of these structures. We currently have six joint ventures that are not consolidated with our financial statements. Our share of the aggregate revenue of these joint ventures represents 2.3% of our total revenue (the sum of our total consolidated revenue and our share of such joint venture revenue). We could become engaged in a dispute with any of our joint ventures that might affect our ability to operate a property. In addition, our joint venture partners may have different objectives than we do regarding the appropriate timing and terms of any sale or refinancing of properties. Finally, in many instances, our joint venture partners have competing interests in our markets that could create conflict of interest issues.

We face risks associated with property acquisitions.

We have and intend to continue to acquire properties and portfolios of properties, including large portfolios that could increase our size and result in alterations to our capital structure. Our acquisition activities and their success are subject to the following risks:

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We have acquired in the past and in the future may acquire properties or portfolios of properties through tax deferred contribution transactions in exchange for partnership interests in Boston Properties Limited Partnership. This acquisition structure has the effect, among others, of reducing the amount of tax depreciation we can deduct over the tax life of the acquired properties, and typically requires that we agree to protect the contributors’ ability to defer recognition of taxable gain through restrictions on our ability to dispose of the acquired properties and/or the allocation of partnership debt to the contributors to maintain their tax bases.

Acquired properties may expose us to unknown liability.

We may acquire properties subject to liabilities and without any recourse, or with only limited recourse, with respect to unknown liabilities. As a result, if a liability were asserted against us based upon ownership of those properties, we might have to pay substantial sums to settle it, which could adversely affect our results of operations and cash flow. Unknown liabilities with respect to acquired properties might include:

Competition for acquisitions may result in increased prices for properties.

We plan to continue to acquire properties as we are presented with attractive opportunities. We may face competition for acquisition opportunities with other investors and this competition may adversely affect us by subjecting us to the following risks:

We face potential difficulties or delays renewing leases or re-leasing space.

We derive most of our income from rent received from our tenants. If a tenant experiences a downturn in its business or other types of financial distress, it may be unable to make timely rental payments. Also, when our tenants decide not to renew their leases or terminate early, we may not be able to re-let the space. Even if tenants decide to renew or lease net space, the terms of renewals or new leases, including the cost of required renovations or concessions to tenants, may be less favorable to us than current lease terms. As a result, our cash flow could decrease and our ability to make distributions to our securityholders could be adversely affected.

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We face potential adverse effects from major tenants’ bankruptcies or insolvencies.

The bankruptcy or insolvency of a major tenant may adversely affect the income produced by our properties. Our tenants could file for bankruptcy protection or become insolvent in the future. We cannot evict a tenant solely because of its bankruptcy. On the other hand, a bankrupt tenant may reject and terminate its lease with us. In such case, our claim against the bankrupt tenant for unpaid and future rent would be subject to a statutory cap that might be substantially less than the remaining rent actually owed under the lease, and, even so, our claim for unpaid rent would likely not be paid in full. This shortfall could adversely affect our cash flow and results of operations.

We may have difficulty selling our properties, which may limit our flexibility.

Large and high-quality office, industrial and hotel properties like the ones that we own could be difficult to sell. This may limit our ability to change our portfolio promptly in response to changes in economic or other conditions. In addition, federal tax laws limit our ability to sell properties that we have owned for fewer than four years and this may affect our ability to sell properties without adversely affecting returns to our securityholders. These restrictions reduce our ability to respond to changes in the performance of our investments and could adversely affect our financial condition and results of operations.

Our ability to dispose of some of our properties is constrained by their tax attributes. Properties which we developed and have owned for a significant period of time or which we acquired through tax deferred contribution transactions in exchange for partnership interests in Boston Properties Limited Partnership often have low tax bases. If we dispose of these properties outright in taxable transactions, we may be required to distribute a significant amount of the taxable gain to our securityholders under the requirements of the Internal Revenue Code for REIT’s like us, which in turn would impact our cash flow. In some cases, without incurring additional costs we may be restricted from disposing of properties contributed in exchange for our partnership interests under tax protection agreements with contributors. To dispose of low basis or tax-protected properties efficiently we often use like-kind exchanges, which qualify for non-recognition of taxable gain, but can be difficult to consummate and result in the property for which the disposed assets are exchanged inheriting their low bases and other tax attributes (including tax protection covenants).

Our properties face significant competition.

We face significant competition from developers, owners and operators of office, industrial and other commercial real estate, including sublease space available from our tenants. Substantially all of our properties face competition from similar properties in the same market. Such competition may affect our ability to attract and retain tenants and may reduce the rents we are able to charge. These competing properties may have vacancy rates higher than our properties, which may result in their owners being willing to make space available at lower prices than the space in our properties.

Because we own three hotel properties, we face the risks associated with the hospitality industry.

Because the lease payments we receive under the hotel leases are based on a participation in the gross receipts of the hotels, if the hotels do not generate sufficient receipts, our cash flow would be decreased, which could reduce the amount of cash available for distribution to our securityholders. The following factors, among others, are common to the hotel industry, and may reduce the receipts generated by our hotel properties:

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In addition, because all three of our hotel properties are located within a two-mile radius in downtown Boston and Cambridge, they are all subject to the Boston market’s fluctuations in demand, increases in operating costs and increased competition from additions in supply.

Because of the ownership structure of our three hotel properties, we face potential adverse effects from changes to the applicable tax laws.

We own three hotel properties. However, under the Internal Revenue Code, REITs like us are not allowed to operate hotels directly or indirectly. Accordingly, we lease our hotel properties to our taxable REIT subsidiary, or TRS. As lessor, we are entitled to a percentage of the gross receipts from the operation of the hotel properties. Marriott International, Inc. manages the hotels under the Marriott^® name pursuant to a management contract with the TRS as lessee. While the TRS structure allows the economic benefits of ownership to flow to us, the TRS is subject to tax on its income from the operations of the hotels at the federal and state level. In addition, the TRS is subject to detailed tax regulations that affect how it may be capitalized and operated. If the tax laws applicable to TRS’s are modified, we may be forced to modify the structure for owning our hotel properties, and such changes may adversely affect the cash flows from our hotels. In addition, the Internal Revenue Service, the United States Treasury Department and Congress frequently review federal income tax legislation, and we cannot predict whether, when or to what extent new federal tax laws, regulations, interpretations or rulings will be adopted. Any of such legislative action may prospectively or retroactively modify the tax treatment of the TRS and, therefore, may adversely affect our after-tax returns from our hotel properties.

Compliance or failure to comply with the Americans with Disabilities Act or other safety regulations and requirements could result in substantial costs.

The Americans with Disabilities Act generally requires that public buildings, including office buildings and hotels, be made accessible to disabled persons. Noncompliance could result in the imposition of fines by the federal government or the award of damages to private litigants. If, pursuant to the Americans with Disabilities Act, we are required to make substantial alterations and capital expenditures in one or more of our properties, including the removal of access barriers, it could adversely affect our financial condition and results of operations, as well as the amount of cash available for distribution to our securityholders.

Our properties are subject to various federal, state and local regulatory requirements, such as state and local fire and life safety requirements. If we fail to comply with these requirements, we could incur fines or private damage awards. We do not know whether existing requirements will change or whether compliance with future requirements will require significant unanticipated expenditures that will affect our cash flow and results of operations.

Some potential losses are not covered by insurance.

We carry insurance coverage on our properties of types and in amounts that we believe are in line with coverage customarily obtained by owners of similar properties. In response to the uncertainty in the insurance market following the terrorist attacks of September 11, 2001, the Federal Terrorism Risk Insurance Act was enacted in November 2002 to require regulated insurers to make available coverage for certified acts of terrorism (as defined by the statute) through December 31, 2004, subject to extension by the United States Department of Treasury through December 31, 2005. The Federal Terrorism Risk Insurance Act expires on December 31, 2005, unless extended, and therefore, we cannot currently anticipate whether the Act will renew upon expiration. In connection with the renewal of coverage for the policy year beginning March 1, 2004, we are currently evaluating coverage on terms and amounts comparable to our existing policies, subject to cost and market availability. Our current property insurance coverage carries a $640 million per occurrence limit, including coverage for certified acts of terrorism. Additionally, our 2003 program provides $25 million of coverage for acts of terrorism other than those “certified” under the Federal Terrorism Risk Insurance Act.

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We also carry earthquake insurance on our properties located in areas known to be subject to earthquakes in an amount and subject to deductibles and self-insurance that we believe are commercially reasonable. Specifically, we carry earthquake insurance which covers our San Francisco portfolio with a $120 million per occurrence limit and a $120 million aggregate limit, $20 million of which is provided as a direct insurer by IXP, Inc. The amount of our earthquake insurance coverage may not be sufficient to cover losses from earthquakes. As a result of increased costs of coverage and decreased availability, the amount of third party earthquake insurance we may be able to purchase on commercially reasonable terms may be reduced. In addition, we may discontinue earthquake insurance on some or all of our properties in the future if the premiums exceed our estimation of the value of the coverage.

In January 2002, we formed a wholly-owned taxable REIT subsidiary, IXP, Inc. (“IXP”), to act as a captive insurance company and be one of the elements of our overall insurance program. IXP acts as a primary carrier with respect to a portion of our earthquake insurance coverage for our Greater San Francisco properties. Insofar as we own IXP, we are responsible for its liquidity and capital resources, and the accounts of IXP are part of our consolidated financial statements. If we experience a loss and IXP is required to pay under its insurance policy, we would ultimately record the loss to the extent of IXP’s required payment. Therefore, insurance coverage provided by IXP should not be considered as the equivalent of third-party insurance, but rather as a modified form of self-insurance. In the future IXP may provide additional or different coverage, as a reinsurer or a primary insurer, depending on the availability and cost of third-party insurance in the marketplace and the level of self-insurance that we believe is commercially reasonable.

We continue to monitor the state of the insurance market in general, and the scope and costs of coverage for acts of terrorism in particular, but we can not anticipate what coverage will be available on commercially reasonable terms in future policy years. There are other types of losses, such as from wars, acts of nuclear, biological or chemical terrorism or the presence of mold at our properties, for which we cannot obtain insurance at all or at a reasonable cost. With respect to such losses and losses from acts of terrorism, earthquakes or other catastrophic events, if we experience a loss that is uninsured or that exceeds policy limits, we could lose the capital invested in the damaged properties, as well as the anticipated future revenues from those properties. Depending on the specific circumstances of each affected property, it is possible that we could be liable for mortgage indebtedness or other obligations related to the property. Any such loss could materially and adversely affect our business and financial condition and results of operations.

Potential liability for environmental contamination could result in substantial costs.

Under federal, state and local environmental laws, ordinances and regulations, we may be required to investigate and clean up the effects of releases of hazardous or toxic substances or petroleum products at our properties simply because of our current or past ownership or operation of the real estate. If unidentified environmental problems arise, we may have to make substantial payments, which could adversely affect our cash flow and our ability to make distributions to our securityholders because:

These costs could be substantial and in extreme cases could exceed the value of the contaminated property. The presence of hazardous or toxic substances or petroleum products or the failure to properly remediate contamination may materially and adversely affect our ability to borrow against, sell or rent an affected property.

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In addition, applicable environmental laws create liens on contaminated sites in favor of the government for damages and costs it incurs in connection with a contamination. Changes in laws increasing the potential liability for environmental conditions existing at our properties, or increasing the restrictions on the handling, storage or discharge of hazardous or toxic substances or petroleum products or other actions may result in significant unanticipated expenditures.

Environmental laws also govern the presence, maintenance and removal of asbestos. Such laws require that owners or operators of buildings containing asbestos:

Such laws may impose fines and penalties on building owners or operators who fail to comply with these requirements and may allow third parties to seek recovery from owners or operators for personal injury associated with exposure to asbestos fibers.

Some of our properties are located in urban, industrial and previously developed areas where fill or current or historic industrial uses of the areas have caused site contamination. It is our policy to retain independent environmental consultants to conduct Phase I environmental site assessments and asbestos surveys with respect to our acquisition of properties. These assessments generally include a visual inspection of the properties and the surrounding areas, an examination of current and historical uses of the properties and the surrounding areas and a review of relevant state, federal and historical documents, but do not involve invasive techniques such as soil and ground water sampling. Where appropriate, on a property-by-property basis, our practice is to have these consultants conduct additional testing, including sampling for asbestos, for lead in drinking water, for soil contamination where underground storage tanks are or were located or where other past site usage create a potential environmental problem, and for contamination in groundwater. Even though these environmental assessments are conducted, there is still the risk that:

Inquiries about indoor air quality may necessitate special investigation and, depending on the results, remediation beyond our regular indoor air quality testing and maintenance programs. Indoor air quality issues can stem from inadequate ventilation, chemical contaminants from indoor or outdoor sources, and biological contaminants such as molds, pollen, viruses and bacteria. Indoor exposure to chemical or biological contaminants above certain levels can be alleged to be connected to allergic reactions or other health effects and symptoms in susceptible individuals. If these conditions were to occur at one of our properties, we may need to undertake a targeted remediation program, including without limitation, steps to increase indoor ventilation rates and eliminate sources of contaminants. Such remediation programs could be costly, necessitate the temporary relocation of some or all of the property’s tenants or require rehabilitation of the affected property.

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We face risks associated with the use of debt to fund acquisitions and developments, including refinancing risk.

We are subject to the risks normally associated with debt financing, including the risk that our cash flow will be insufficient to meet required payments of principal and interest. We anticipate that only a small portion of the principal of our debt will be repaid prior to maturity. Therefore, we are likely to need to refinance at least a portion of our outstanding debt as it matures. There is a risk that we may not be able to refinance existing debt or that the terms of any refinancing will not be as favorable as the terms of our existing debt. If principal payments due at maturity cannot be refinanced, extended or repaid with proceeds from other sources, such as new equity capital, our cash flow will not be sufficient to repay all maturing debt in years when significant “balloon” payments come due.

We have agreements with a number of limited partners of Boston Properties Limited Partnership who contributed properties in exchange for partnership interests that require Boston Properties Limited Partnership to maintain for specified periods of time secured debt on certain of our assets and/or allocate partnership debt to such limited partners to enable them to continue to defer recognition of their taxable gain with respect to the contributed property. These tax protection and debt allocation agreements may restrict our ability to repay or refinance debt.

An increase in interest rates would increase our interest costs on variable rate debt and could adversely impact our ability to refinance existing debt or sell assets.

As of December 31, 2003, we had approximately $439 million, and may incur more, of indebtedness that bears interest at variable rates. Accordingly, if interest rates increase, so will our interest costs, which would adversely affect our cash flow and our ability to pay principal and interest on our debt and our ability to make distributions to our securityholders. Further, rising interest rates could limit our ability to refinance existing debt when it matures. We may from time to time enter into agreements such as interest rate swaps, caps, floors and other interest rate hedging contracts with respect to a portion of our variable rate debt. While these agreements may lessen the impact of rising interest rates on us, they also expose us to the risk that other parties to the agreements will not perform or that the agreements will be unenforceable. In addition, an increase in interest rates could decrease the amount third-parties are willing to pay for our assets, thereby limiting our ability to change our portfolio promptly in respect to changes in economic or other conditions.

Covenants in our debt agreements could adversely affect our financial condition.

The mortgages on our properties contain customary covenants such as those that limit our ability, without the prior consent of the lender, to further mortgage the applicable property or to discontinue insurance coverage. Our unsecured credit facility, unsecured debt securities and secured construction loans contain customary restrictions, requirements and other limitations on our ability to incur indebtedness, including total debt to asset ratios, secured debt to total asset ratios, debt service coverage ratios and minimum ratios of unencumbered assets to unsecured debt, which we must maintain. Our continued ability to borrow under our credit facilities is subject to compliance with our financial and other covenants. In addition, our failure to comply with such covenants could cause a default under the applicable debt agreement, and we may then be required to repay such debt with capital from other sources. Under those circumstances, other sources of capital may not be available to us, or be available only on unattractive terms. Additionally, in the future our ability to satisfy current or prospective lenders’ insurance requirements may be adversely affected if lenders generally insist upon greater insurance coverage against acts of terrorism than is available to us in the marketplace or on commercially reasonable terms.

We rely on debt financing, including borrowings under our unsecured credit facility, issuances of unsecured debt securities and debt secured by individual properties, to finance our acquisition and development activities and for working capital. If we are unable to obtain debt financing from these or other sources, or to refinance existing indebtedness upon maturity, our financial condition and results of operations would likely be adversely

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affected. If we breach covenants in our debt agreements, the lenders can declare a default and, if the debt is secured, can take possession of the property securing the defaulted loan. In addition, our unsecured debt agreements contain specific cross-default provisions with respect to specified other indebtedness, giving the unsecured lenders the right to declare a default if we are in default under other loans in some circumstances. Defaults under our debt agreements could materially and adversely affect our financial condition and results of operations.

Our degree of leverage could limit our ability to obtain additional financing or affect the market price of our common stock or debt securities.

On February 18, 2004, we had approximately $5.1 billion in total indebtedness outstanding on a consolidated basis (excluding unconsolidated joint venture debt). Debt to market capitalization ratio, which measures total debt as a percentage of the aggregate of total debt plus the market value of outstanding equity securities, is often used by analysts to gauge leverage for equity REITs such as us. Our market value is calculated using the price per share of our common stock. Using the closing stock price of $51.48 per share of our common stock of Boston Properties, Inc. on February 18, 2004, multiplied by the sum of (1) the actual aggregate number of outstanding common partnership units of Boston Properties Limited Partnership (including common partnership units held by us) and (2) the number of common partnership units available upon conversion of preferred partnership units of Boston Properties Limited Partnership, our debt to market capitalization ratio was approximately 43.3% as of February 18, 2004.

Our degree of leverage could affect our ability to obtain additional financing for working capital, capital expenditures, acquisitions, development or other general corporate purposes. Our senior unsecured debt is currently rated investment grade by the three major rating agencies. However, there can be no assurance we will be able to maintain this rating, and in the event our senior debt is downgraded from its current rating, we would likely incur higher borrowing costs. Our degree of leverage could also make us more vulnerable to a downturn in business or the economy generally.

Further issuances of equity securities may be dilutive to current securityholders.

The interests of our existing securityholders could be diluted if additional equity securities are issued to finance future developments, acquisitions, or repay indebtedness. Our ability to execute our business strategy depends on our access to an appropriate blend of debt financing, including unsecured lines of credit and other forms of secured and unsecured debt, and equity financing, including common and preferred equity.

Failure to qualify as a real estate investment trust would cause us to be taxed as a corporation, which would substantially reduce funds available for payment of dividends.

If we fail to qualify as a real estate investment trust, or REIT, for federal income tax purposes, we will be taxed as a corporation. We believe that we are organized and qualified as a REIT and intend to operate in a manner that will allow us to continue to qualify as a REIT. However, we cannot assure you that we are qualified as such, or that we will remain qualified as such in the future. This is because qualification as a REIT involves the application of highly technical and complex provisions of the Internal Revenue Code as to which there are only limited judicial and administrative interpretations, and involves the determination of facts and circumstances not entirely within our control. Future legislation, new regulations, administrative interpretations or court decisions may significantly change the tax laws or the application of the tax laws with respect to qualification as a REIT for federal income tax purposes or the federal income tax consequences of such qualification.

In addition, we currently hold certain of our properties through a subsidiary that has elected to be taxed as a REIT and we may in the future determine that it is in our best interests to hold one or more of our other properties through one or more subsidiaries that elect to be taxed as REITs. If any of these subsidiaries fails to

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qualify as a REIT for federal income tax purposes, then we may also fail to qualify as a REIT for federal income tax purposes.

If we fail to qualify as a REIT we will face serious tax consequences that will substantially reduce the funds available for payment of dividends for each of the years involved because:

In addition, if we fail to qualify as a REIT, we will no longer be required to pay dividends. As a result of all these factors, our failure to qualify as a REIT could impair our ability to expand our business and raise capital, and would adversely affect the value of our common stock.

In order to maintain our REIT status, we may be forced to borrow funds during unfavorable market conditions.

In order to maintain our REIT status, we may need to borrow funds on a short-term basis to meet the real estate investment trust distribution requirements, even if the then prevailing market conditions are not favorable for these borrowings. To qualify as REIT, we generally must distribute to our stockholders at least 90% of our net taxable income each year, excluding capital gains. In addition, we will be subject to a 4% nondeductible excise tax on the amount, if any, by which dividends paid by us in any calendar year are less than the sum of 85% of our ordinary income, 95% of our capital gain net income and 100% of our undistributed income from prior years. We may need short-term debt or long-term debt, proceeds from asset sales, creation of joint ventures or sale of common stock to fund required distributions as a result of differences in timing between the actual receipt of income and the recognition of income for federal income tax purposes, or the effect of non-deductible capital expenditures, the creation of reserves or required debt or amortization payments.

Limits on changes in control may discourage takeover attempts beneficial to stockholders.

Provisions in our certificate of incorporation and bylaws, our shareholder rights agreement and the limited partnership agreement of Boston Properties Limited Partnership, as well as provisions of the Internal Revenue Code and Delaware corporate law, may:

Stock Ownership Limit

Primarily to facilitate maintenance of our qualification as a REIT, our certificate of incorporation generally prohibits ownership, directly, indirectly or beneficially, by any single stockholder of more than 6.6% of the number of outstanding shares of any class or series of our equity stock. We refer to this limitation as the “ownership limit.” Our board of directors may waive or modify the ownership limit with respect to one or more

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persons if it is satisfied that ownership in excess of this limit will not jeopardize our status as a REIT for federal income tax purposes. In addition, under our certificate of incorporation each of Mortimer B. Zuckerman and Edward H. Linde, along with their respective families and affiliates, as well as, in general, pension plans and mutual funds, may actually and beneficially own up to 15% of the number of outstanding shares of any class or series of our equity common stock. Shares owned in violation of the ownership limit will be subject to the loss of rights to distributions and voting and other penalties. The ownership limit may have the effect of inhibiting or impeding a change in control.

Boston Properties Limited Partnership Agreement

We have agreed in the limited partnership agreement of Boston Properties Limited Partnership not to engage in business combinations unless limited partners of Boston Properties Limited Partnership other than Boston Properties, Inc. receive, or have the opportunity to receive, the same consideration for their partnership interests as holders of our common stock in the transaction. If these limited partners would not receive such consideration, we cannot engage in the transaction unless 75% of these limited partners vote to approve the transaction. In addition, we have agreed in the limited partnership agreement of Boston Properties Limited Partnership that we will not complete business combinations in which we receive the approval of our stockholders unless these limited partners are also allowed to vote and the transaction would have been approved had these limited partners been able to vote as stockholders on the transaction. Therefore, if our stockholders approve a business combination that requires a vote of stockholders, the partnership agreement requires the following before we can complete the transaction:

As a result of these provisions, a potential acquirer may be deterred from making an acquisition proposal and we may be prohibited by contract from engaging in a proposed business combination even though our stockholders approve of the combination.

Shareholder Rights Plan

We have a shareholder rights plan. Under the terms of this plan, we can in effect prevent a person or group from acquiring more than 15% of the outstanding shares of our common stock, because, unless we approve of the acquisition, after the person acquires more than 15% of our outstanding common stock, all other stockholders will have the right to purchase securities from us at a price that is less than their then fair market value, which would substantially reduce the value and influence of the stock owned by the acquiring person. Our board of directors can prevent the plan from operating by approving the transaction in advance, which gives us significant power to approve or disapprove of the efforts of a person or group to acquire a large interest in our company.

We may change our policies without obtaining the approval of our stockholders.

Our operating and financial policies, including our policies with respect to acquisitions or real estate, growth, operations, indebtedness, capitalization and dividends, are exclusively determined by our board of directors. Accordingly, our stockholders do not control these policies.

Our success depends on key personnel whose continued service is not guaranteed.

We depend on the efforts of key personnel, particularly Mortimer B. Zuckerman, Chairman of our board of directors, and Edward H. Linde, our President and Chief Executive Officer. Among the reasons that Messrs.

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Zuckerman and Linde are important to our success is that each has a national reputation, which attracts business and investment opportunities and assists us in negotiations with lenders. If we lost their services, our relationships with lenders, potential tenants and industry personnel could diminish. Mr. Zuckerman has substantial outside business interests that could interfere with his ability to devote his full time to our business and affairs.

Our two Executive Vice Presidents, Chief Financial Officer and other executive officers that serve as managers of our regional offices also have strong reputations. Their reputations aid us in identifying opportunities, having opportunities brought to us, and negotiating with tenants and build-to-suit prospects. While we believe that we could find replacements for these key personnel, the loss of their services could materially and adversely affect our operations because of diminished relationships with lenders, prospective tenants and industry personnel.

Conflicts of interest exist with holders of interests in Boston Properties Limited Partnership.

Sales of properties and repayment of related indebtedness will have different effects on holders of interests in Boston Properties Limited Partnership than on our stockholders.

Some holders of interests in Boston Properties Limited Partnership, including Messrs. Zuckerman and Linde, would incur adverse tax consequences upon the sale of certain of our properties and on the repayment of related debt which differ from the tax consequences to us and our stockholders. Consequently, these holders of partnership interests in Boston Properties Limited Partnership may have different objectives regarding the appropriate pricing and timing of any such sale or repayment of debt. While we have exclusive authority under the limited partnership agreement of Boston Properties Limited Partnership to determine when to refinance or repay debt or whether, when, and on what terms to sell a property, subject, in the case of certain properties, to the contractual commitments described below, any such decision would require the approval of our board of directors. As directors and executive officers, Messrs. Zuckerman and Linde could exercise their influence in a manner inconsistent with the interests of some, or a majority, of our stockholders, including in a manner which could prevent completion of a sale of a property or the repayment of indebtedness.

Agreement not to sell some properties.

Under the terms of the limited partnership agreement of Boston Properties Limited Partnership, we have agreed not to sell or otherwise transfer some of our properties, prior to specified dates, in any transaction that would trigger taxable income, without first obtaining the consent of Messrs. Zuckerman and Linde. However, we are not required to obtain their consent if, during the applicable period, each of them does not hold at least 30% of his original interests in Boston Properties Limited Partnership, or if those properties are transferred in a nontaxable event. In addition, we have entered into similar agreements with respect to other properties that we have acquired in exchange for partnership interests in Boston Properties Limited Partnership. Pursuant to those agreements, we are responsible for the reimbursement of tax costs to the prior owners if the subject properties are sold in a taxable sale. Our obligations to the prior owners are generally limited in time and only apply to actual damages suffered. As of December 31, 2003, there were a total of 33 properties subject to these restrictions, and those properties are estimated to have accounted for approximately 55.1% of our total revenue for the year ended December 31, 2003.

Boston Properties Limited Partnership has also entered into agreements providing prior owners of properties with the right to guarantee specific amounts of indebtedness and, in the event that the specific indebtedness they guarantee is repaid or reduced, additional and/or substitute indebtedness. These agreements may hinder actions that we may otherwise desire to take to repay or refinance guaranteed indebtedness because we would be required to make payments to the beneficiaries of such agreements if we violate these agreements.

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Messrs. Zuckerman and Linde will continue to engage in other activities.

Messrs. Zuckerman and Linde have a broad and varied range of investment interests. Either one could acquire an interest in a company which is not currently involved in real estate investment activities but which may acquire real property in the future. However, pursuant to each of their employment agreements, Messrs. Zuckerman and Linde will not, in general, have management control over such companies and, therefore, they may not be able to prevent one or more such companies from engaging in activities that are in competition with our activities.

Changes in market conditions could adversely affect the market price of our common stock.

As with other publicly traded equity securities, the value of our common stock depends on various market conditions that may change from time to time. Among the market conditions that may affect the value of our common stock are the following:

The market value of our common stock is based primarily upon the market’s perception of our growth potential and our current and potential future earnings and cash dividends. Consequently, our common stock may trade at prices that are higher or lower than our net asset value per share of common stock. If our future earnings or cash dividends are less than expected, it is likely that the market price of our common stock will diminish.

The number of shares available for future sale could adversely affect the market price of our stock.

In connection with and subsequent to our initial public offering, we have completed many private placement transactions in which shares of capital stock of Boston Properties, Inc. or partnership interests in Boston Properties Limited Partnership were issued to owners of properties we acquired or to institutional investors. This common stock, or common stock issuable on conversion of preferred stock or in exchange for such partnership interests in Boston Properties Limited Partnership, may be sold in the public securities markets over time under registration rights we granted to these investors. Additional common stock reserved under our employee benefit and other incentive plans, including stock options and restricted stock, may also be sold in the market at some time in the future. Future sales of our common stock in the market could adversely affect the price of our common stock. We cannot predict the effect the perception in the market that such sales may occur will have on the market price of our common stock.

We did not obtain new owner’s title insurance policies in connection with properties acquired during our initial public offering.

We acquired many of our properties from our predecessors at the completion of our initial public offering in June 1997. Before we acquired these properties each of them was insured by a title insurance policy. We did not

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obtain new owner’s title insurance policies in connection with the acquisition of these properties, however, to the extent we have financed properties acquired in connection with the IPO, we have obtained new title insurance policies. Nevertheless, because in many instances we acquired these properties indirectly by acquiring ownership of the entity which owned the property and those owners remain in existence as our subsidiaries, some of these title insurance policies may continue to benefit us. Many of these title insurance policies may be for amounts less than the current values of the applicable properties. If there was a title defect related to any of these properties, or to any of the properties acquired at the time of our initial public offering, that is no longer covered by a title insurance policy, we could lose both our capital invested in and our anticipated profits from such property. We have obtained title insurance policies for all properties that we have acquired after our initial public offering.

We face possible adverse changes in tax laws.

From time to time changes in state and local tax laws or regulations are enacted, which may result in an increase in our tax liability. The shortfall in tax revenues for states and municipalities in recent years may lead to an increase in the frequency and size of such changes. If such changes occur, we may be required to pay additional taxes on our assets or income and may be assessed interest and penalties on such additional taxes. These increased tax costs could adversely affect our financial condition and results of operations and the amount of cash available for payment of dividends.

At December 31, 2003, our portfolio consisted of 140 properties totaling 43.9 million net rentable square feet. Our properties consisted of (1) 131 office properties, comprised of 103 Class A office buildings, including three properties under construction and 28 properties that support both office and technical uses, (2) four industrial properties, (3) two retail properties, and (4) three hotels. In addition, we own or control 43 parcels of land for future development. The following table sets forth information relating to the properties we owned, or had an ownership interest in, at December 31, 2003:

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Top 20 Tenants by Square Feet

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Lease Expirations

We are subject to various legal proceedings and claims that arise in the ordinary course of business. These matters are generally covered by insurance. Management believes that the final outcome of such matters will not have a material adverse effect on our financial position, results of operations or liquidity.

No matters were submitted to a vote of our stockholders during the fourth quarter of the year ended December 31, 2003.

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PART II

Our common stock is listed on the New York Stock Exchange under the symbol “BXP.” The high and low sales prices for the periods indicated in the table below were:

At February 18, 2004, we had approximately 1,272 stockholders of record. This does not include beneficial owners for whom Cede & Co. or others act as nominee.

In order to maintain our qualification as a REIT, we must make annual distributions to our stockholders of at least 90% of our taxable income (not including net capital gains). We have adopted a policy of paying regular quarterly distributions on our common stock, and cash distributions have been paid on our common stock since our initial public offering. Distributions are declared at the discretion of the Board of Directors and depend on actual cash from operations, our financial condition, capital requirements, the annual distribution requirements under the REIT provisions of the Internal Revenue Code and other factors the Board of Directors may consider relevant.

During the three months ended December 31, 2003, we issued 2,499 shares of common stock in exchange for 2,499 units of limited partnership held by certain limited partners of Boston Properties Limited Partnership. These shares were issued in reliance on an exemption from registration under Section 4(2) of the Securities Act of 1933. We are relying on the exemption based upon factual representations received from the limited partners who received these shares.

The following table sets forth our selected financial and operating data on an historical basis, which has been revised for the reclassification of losses from early extinguishments of debt, in accordance with SFAS No. 145 and the disposition of properties during 2002 and 2003 which have been reclassified as discontinued operations, for the periods presented, in accordance with SFAS No. 144. Refer to Notes 15 and 22 of the Consolidated Financial Statements. The following data should be read in conjunction with our financial statements and notes thereto and Management’s Discussion and Analysis of Financial Condition and Results of Operations included elsewhere in this Form 10-K.

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Our historical operating results may not be comparable to our future operating results.