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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, 2004

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.  x

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, 2004, the aggregate market value of the 5,821,477 shares of common stock held by non-affiliates of the Registrant was $291,539,568 based upon the last reported sale price of $50.08 per share on the New York Stock Exchange on June 30, 2004. (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 March 4, 2005, there were 110,374,075 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 11, 2005 is incorporated by reference in Part III, Items 10, 11, 12, 13 and 14. The Registrant will file such Proxy Statement with the Securities and Exchange Commission not later than 120 days after the end of its fiscal year ended December 31, 2004.

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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, 2004, we owned or had interests in 125 properties, totaling approximately 44.1 million net rentable square feet and structured parking for 31,270 vehicles containing approximately 9.5 million square feet. Our properties consisted of:

We own or control undeveloped land totaling approximately 543 acres which will support approximately 11.3 million square feet of development. In addition, we have a 25% interest in the Boston Properties Office Value-Added Fund, L.P., which we refer to as the “Value-Added Fund,” which is a strategic partnership with two institutional investors through which we intend to pursue the acquisition of assets within our existing markets that have deficiencies in property characteristics which provide an opportunity to create value through repositioning, refurbishment or renovation. Our investments through the Value-Added Fund are not included in our portfolio information tables or any other portfolio level statistics.

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 definitions of Class A office and Office/Technical properties may be different than those used by 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, 2004, we had approximately 667 employees. Our 30 senior officers have an average of 24 years experience in the real estate industry and an average of 16 years of experience with us. Our principal executive office is located at 111 Huntington Avenue, Boston, Massachusetts 02199 and our 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, or the SEC. The name “Boston Properties” and our logo (consisting of a stylized “b”) are registered service marks of the Company.

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Boston Properties Limited Partnership

Boston Properties Limited Partnership, or BPLP, is a Delaware limited partnership, and 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 March 4, 2005, the owner of approximately 80.2% of the economic interests in BPLP. Economic interest was calculated as the number of common partnership units of BPLP owned by the Company as a percentage of the sum of (1) the actual aggregate number of outstanding common partnership units of BPLP, (2) the number of common partnership units issuable upon conversion of outstanding preferred partnership units of BPLP and (3) the number of common units issuable upon conversion of all outstanding long term incentive plan units of BPLP, or LTIP units, assuming all conditions have been met for the conversion of the LTIP units. Our general and limited partnership interests in BPLP entitle us to share in cash distributions from, and in the profits and losses of, BPLP 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 BPLP are persons who contributed their direct or indirect interests in properties to BPLP in exchange for common units or preferred units of limited partnership interest in BPLP. Under the limited partnership agreement of BPLP, unitholders may present their common units of BPLP 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 cash redemption by BPLP, however, we may elect to acquire any common units so tendered by issuing shares of our 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 BPLP pay cash. With each such exchange or redemption, our percentage ownership in BPLP 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 BPLP and BPLP must issue to us an equivalent number of common units of BPLP. This structure is commonly referred to as an umbrella partnership REIT or “UPREIT.”

Preferred units of BPLP have the rights, preferences and other privileges, including the right to convert into common units of BPLP, as are set forth in amendments to the limited partnership agreement of BPLP. As of December 31, 2004 and March 4, 2005, BPLP had one series of its preferred units outstanding. The Series Two preferred units have an aggregate liquidation preference of approximately $204.1 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 greater 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 greater 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 preferred 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 BPLP any Series Two preferred units that are not redeemed when they are eligible for redemption.

Significant Transactions During 2004

Real Estate Acquisitions/Dispositions

On December 8, 2004, we sold 560 Forbes Boulevard in South San Francisco, California, an industrial property totaling approximately 40,000 square feet, for net proceeds of approximately $3.8 million, resulting in a gain on sale of approximately $1.1 million, net of minority interest share of approximately $2.7 million.

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On October 25, 2004, we formed the Value-Added Fund, which is a strategic partnership with two institutional investors, to pursue the acquisition of assets within our existing markets that have deficiencies in property characteristics which provide an opportunity to create value through repositioning, refurbishment or renovation. The Value-Added Fund has total equity commitments of $140 million, of which we have committed $35 million. Assuming an estimated 65% leverage ratio, the Value-Added Fund is anticipated to have up to $400 million of total investments. We will receive asset management, property management, leasing and redevelopment fees and, if certain return thresholds are achieved, will be entitled to an additional promoted interest. On November 1, 2004, the Value-Added Fund completed the acquisition of Worldgate Plaza, a 322,000 square foot office complex located in Herndon, Virginia for a purchase price of approximately $78.2 million. The acquisition was financed with new mortgage indebtedness totaling $57.0 million and approximately $21.2 million in cash, of which our share was $5.3 million. The mortgage financing bears interest at a variable rate equal to LIBOR plus 0.89% per annum and matures in October 2007, with two one-year extension options. In addition, the Value-Added Fund entered into an agreement to cap the interest rate at 9.5% per annum for a nominal fee.

On September 28, 2004, we sold 204 Second Avenue in Waltham, Massachusetts, a Class A office property totaling approximately 41,000 square feet, for net proceeds of approximately $5.7 million, resulting in a gain on sale of approximately $3.5 million, net of minority interest share of approximately $0.7 million.

On August 1, 2004, we sold Sugarland Business Park- Building One in Herndon, Virginia, an office/technical property totaling approximately 52,000 square feet, for net proceeds of approximately $7.6 million, resulting in a gain on sale of approximately $0.6 million, net of minority interest share of approximately $0.1 million.

On June 10, 2004, we sold a land parcel on Burlington Mall Road in Burlington, Massachusetts, for net proceeds of approximately $1.9 million, resulting in a gain on sale of approximately $1.4 million, net of minority interest share of approximately $0.3 million.

On May 21, 2004, we sold 38 Cabot Boulevard in Langhorne, Pennsylvania, an industrial building totaling approximately 161,000 square feet, for net proceeds of approximately $5.5 million, resulting in a gain on sale of approximately $3.5 million, net of minority interest share of approximately $0.7 million.

On April 1, 2004, we sold The Arboretum in Reston, Virginia, a Class A office property totaling approximately 96,000 square feet, for net proceeds of approximately $21.1 million, resulting in a gain on sale of approximately $6.6 million, net of minority interest share of approximately $1.4 million.

On April 1, 2004, we sold Decoverly Two, Three, Six and Seven, consisting of two Class A office properties totaling 155,000 square feet and two land parcels, one of which is subject to a ground lease, for net proceeds of approximately $41.2 million, resulting in a gain on sale of approximately $9.4 million, net of minority interest share of approximately $1.9 million.

On April 1, 2004, we acquired 1330 Connecticut Avenue, a 259,000 square foot Class A office property in Washington, D.C., at a purchase price of $86.6 million. In addition, we paid $1.4 million of closing costs and as of December 31, 2004 we were obligated to fund $7.5 million for tenant and capital improvements during the first two years of ownership. The acquisition was financed with the assumption of mortgage indebtedness secured by the property totaling $52.4 million, which bears interest at a fixed rate of 7.58% per annum and matures in 2011, and available cash. The property is 99% leased.

On March 24, 2004, we acquired the remaining outside interests in our 140 Kendrick Street joint venture properties located in Needham, Massachusetts for cash of $21.6 million and the assumption of the outside partner’s share of the mortgage debt on the properties of approximately $41.6 million.

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On February 10, 2004, we sold Sugarland Business Park- Building Two in Herndon, Virginia, an office/technical property totaling approximately 59,000 square feet, for net proceeds of approximately $6.8 million, resulting in a gain on sale of approximately $2.0 million, net of minority interest share of approximately $0.4 million.

On February 4, 2004, we sold Hilltop Office Center in South San Francisco, consisting of nine office/technical buildings totaling approximately 143,000 square feet, for net proceeds of approximately $11.6 million and the assumption by the buyer of the mortgage debt on the properties totaling $5.2 million, resulting in a gain on sale of approximately $6.8 million, net of minority interest share of approximately $8.7 million.

On January 16, 2004, we sold 430 Rozzi Place in South San Francisco, an industrial property totaling 20,000 square feet, for net proceeds of approximately $2.4 million, resulting in a gain on sale of approximately $0.5 million, net of minority interest share of approximately $1.6 million.

Developments

During 2004, we placed Times Square Tower in New York City and New Dominion Technology Park, Building Two in Herndon, VA into service, which required a total investment during 2004 of approximately $92.0 million, of which $90.7 million was funded through construction loans. Our total investment, including equity and debt, through December 31, 2004 in these properties was approximately $648.0 million. In January 2004, we refinanced the construction loan secured by Times Square Tower, and in September 2004 we refinanced our New Dominion Technology Park, Building Two property by replacing the construction loan with a fixed rate mortgage.

We continued construction on 901 New York Avenue, in which we have a 25% interest, and incurred approximately $12.8 million of construction costs during 2004, of which $8.2 million was funded through an existing construction loan. In December 2004, we refinanced the property by replacing the construction loan with a fixed rate mortgage.

In September 2004, we commenced the redevelopment of our Capital Gallery property in Washington, D.C. Capital Gallery is a Class A office property totaling approximately 397,000 square feet. The project entails removing a three-story, low-rise section of the property comprised of approximately 100,000 square feet from in-service status and redeveloping it into a 10-story office building resulting in a total complex size of approximately 610,000 square feet upon completion. During 2004, we incurred approximately $4.4 million of construction costs, funded through available cash. We expect the development to be completed by the end of 2005. On February 17, 2005, we obtained construction financing totaling $47.2 million which bears interest at a variable rate equal to LIBOR plus 1.65% per annum and matures in February 2008.

On August 2, 2004, we entered into a joint venture with two unrelated third parties to pursue the development of a Class A office building totaling approximately 305,000 square feet that will be part of a mixed-use development of office, retail and residential properties known as Wisconsin Place located in Chevy Chase, Maryland. The new development will sit above a shared four-story parking garage with over 1,700 parking spaces. We have a 66.67% interest in the office building, a shared interest in the infrastructure, a nominal interest in the retail component and no interest in the residential component. During 2004, we incurred approximately $4.2 million of construction costs related to the infrastructure, funded through available cash. No date has yet been determined for commencement of the office component.

On July 30, 2004, we entered into a lease with a tenant totaling approximately 182,000 square feet related to the development of a build-to-suit office building at 12290 Sunrise Valley in Reston, Virginia. The tenant currently leases more than 500,000 square feet in two buildings within the existing office complex. During 2004, we incurred approximately $6.5 million of construction costs, funded through available cash. We expect the development to be completed in the second quarter of 2006.

In July 2004, we commenced construction of Seven Cambridge Center, a fully-leased, build-to-suit project with approximately 231,000 square feet of office, research laboratory and retail space plus parking for

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approximately 800 cars, located in Cambridge, Massachusetts. We signed a lease for 100% of the space with the Massachusetts Institute of Technology for occupancy by its affiliate, the Eli and Edythe L. Broad Institute. During 2004, we incurred approximately $23.0 million of construction costs, funded through available cash. We expect the development to be completed in the first quarter of 2006.

In 2005, we expect to fund future development costs for the development projects begun in 2004 using available cash, our unsecured line of credit and construction loans. The construction costs we expect to incur on our developments can be found within our Contractual Obligations table located on page 72.

Equity Transactions

On March 3, 2004, we completed a public offering of 5,700,000 shares of our common stock at a price to the public of $51.40 per share. The proceeds from this public offering, net of underwriters’ discount and offering costs, totaled approximately $291.1 million. We used the proceeds for the following purposes:

The remainder of the cash proceeds has been retained to fund our current development pipeline, for possible future acquisitions and for general corporate purposes.

During the year ended December 31, 2004, Boston Properties Limited Partnership redeemed 1,318,327 of its Series Two preferred units by converting them into 1,730,084 common units of limited partnership interest. The common units of limited partnership interest were subsequently presented by the holders for redemption and were redeemed by us in exchange for an equal number of shares of common stock. In addition, during the year ended December 31, 2004, we redeemed an aggregate of 810,368 common units of limited partnership interest, presented by the holders for redemption, in exchange for an equal number of shares of common stock. During the year ended December 31, 2004, we issued 3,814,274 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:

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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 for development. 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 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 through 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 as the current economic conditions improve, our office properties will add to our internal growth because of their desirable locations. In addition, we believe that with the continued improvement in the business and leisure travel sector, our hotel properties will continue to 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 7.6 years at December 31, 2004 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, 2004, leases with respect to 5.2% of the total square feet from our Class A office properties will expire in calendar year 2005.

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.

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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 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 of real estate interests consistent with our qualification as a REIT. 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. 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.

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 the Board of Directors or a committee thereof. Some holders of limited partnership interests in BPLP, 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 BPLP 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. Certain assets are subject to tax protection agreements and may limit our ability to dispose such assets.

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Financing Policies

The agreement of limited partnership of BPLP and our certificate of incorporation and bylaws do not limit the amount or percentage of indebtedness that we may incur. 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. 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 BPLP as a whole to generate cash flow to cover expected debt service.

Policies with Respect to Other Activities

As the sole general partner of BPLP, we have the authority to issue additional common and preferred units of limited partnership interest of BPLP. We have in the past, and may in the future, issue common or preferred units of limited partnership interest of BPLP 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 BPLP. We have not engaged in trading, underwriting or agency distribution or sale of securities of issuers other than BPLP and we do not intend to do so. At all times, 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 BPLP, is the lessee pursuant to leases for each of the hotel properties. As lessor, BPLP 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

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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 2004, 2003 and 2002, Marriott received an aggregate of approximately $4.0 million, $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 the percentage of net operating income by quarter over the year ended December 31, 2004 as follows:

Corporate Governance

Boston Properties is currently managed by a ten member Board of Directors, which is divided into three classes (Class I, Class II and Class III). Our Board of Directors is currently composed of four Class I directors (Mortimer B. Zuckerman, Carol B. Einiger, Alan B. Landis and Richard E. Salomon), three Class II directors (Lawrence S. Bacow, Alan J. Patricof and Martin Turchin) and three Class III directors (William M. Daley, Edward H. Linde and David A. Twardock). The members of each class of our Board of Directors serve for three-year terms, and the terms of our current Class I, Class II and Class III directors expire upon the election and qualification of directors at the annual meetings of stockholders held in 2007, 2005 and 2006, respectively. At each annual meeting of stockholders, directors will be re-elected or elected for a full term of three years to succeed those directors whose terms are expiring. Alan B. Landis has resigned from the Board of Directors effective as of immediately prior to the 2005 annual meeting.

Our Board of Directors has the following three committees: (1) Audit, (2) Compensation and (3) Nominating and Corporate Governance. The membership of each of these committees at December 31, 2004 is described below.

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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 BPLP together as our “securities,” and the investors who own shares or units, or both, 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 37.

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 2004 were derived from properties located in our four core markets: Boston, Washington, D.C., midtown Manhattan and San Francisco. A downturn in the economies of these markets, or the impact that a downturn in the overall national economy may have upon these economies, could result in 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 contractors as well as legal firms. In our midtown Manhattan market we have historically leased properties to financial, legal and other professional firms. 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 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 seven joint ventures that are not consolidated with our financial statements. Our share of the aggregate revenue of these joint ventures represents 2.1% of our total revenue (the sum of our total consolidated revenue and our share of such joint venture revenue). Our participation in joint ventures is subject to the risks that:

In addition, our ability to enter into other joint ventures with third parties to pursue the acquisition of value-added investments similar to those being pursued by the Value-Added Fund is limited by the terms of the Value-Added Fund’s partnership agreement.

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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:

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 BPLP. 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. These restrictions on dispositions could limit our ability to sell an asset at a time, or on terms, that would be favorable absent such restrictions.

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 or contest 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:

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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 new 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.

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 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 BPLP 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 REITs, 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. This 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 lease available space at lower prices than the space in our properties.

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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:

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 actions 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, under 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.

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Some potential losses are not covered by insurance.

We carry insurance coverage on our properties of types and in amounts and with deductibles 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, or TRIA, 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, which date was extended to December 31, 2005 by the United States Department of Treasury on June 18, 2004. TRIA expires on December 31, 2005, and we cannot currently anticipate whether it will be extended. Our current property insurance program provides an $890 million per occurrence limit for both “certified” and “non-certified” acts of terrorism as defined by TRIA. We also carry nuclear, biological and chemical terrorism insurance coverage (“NBC Coverage”) with a $640 million per occurrence limit for “certified” acts of terrorism as defined by TRIA, which is provided by IXP, Inc. as a direct insurer. Under TRIA, this NBC Coverage is backstopped by the Federal Government after the payment of the required deductible and 10% coinsurance. This coverage provided by IXP expires on May 1, 2005. We currently intend to extend such coverage for so long as TRIA is in effect and are evaluating whether to increase the amount of the coverage. In the event TRIA is not extended beyond December 31, 2005, (1) the NBC Coverage provided by IXP will terminate, and (2) we have the right to replace a portion of coverage for acts of terrorism (other than NBC Coverage) that would have constituted both “certified” and “non-certified” acts of terrorism had TRIA not expired. We intend to continue to monitor the scope, nature and cost of available terrorism insurance and maintain insurance in amounts and on terms that are commercially reasonable.

We also currently 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 currently 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 by IXP, Inc., as a direct insurer. 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 limited availability, the amount of third-party earthquake insurance that 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., or IXP, to act as a captive insurance company and be one of the elements of our overall insurance program. IXP acts as a direct insurer with respect to a portion of our earthquake insurance coverage for our Greater San Francisco properties and our NBC Coverage for “certified acts of terrorism” under TRIA. 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.

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 cannot anticipate what coverage will be available on commercially reasonable terms in future policy years. There are other types of losses, such as from wars 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.

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Actual or Threatened Terrorist Attacks may Adversely Affect our Ability to Generate Revenues and the Value of our Properties.

We have significant investments in large metropolitan markets that have been or may be in the future the targets of actual or threatened terrorism attacks, including midtown Manhattan, Washington, D.C., Boston and San Francisco. As a result, some tenants in these markets may choose to relocate their businesses to other markets or to lower-profile office buildings within these markets that may be perceived to be less likely targets of future terrorist activity. This could result in an overall decrease in the demand for office space in these markets generally or in our properties in particular, which could increase vacancies in our properties or necessitate that we lease our properties on less favorable terms or both. In addition, future terrorist attacks in these markets could directly or indirectly damage our properties, both physically and financially, or cause losses that materially exceed our insurance coverage. As a result of the foregoing, our ability to generate revenues and the value of our properties could decline materially. See also “—Some potential losses are not covered by insurance.”

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 amount of our insurance or the value of the contaminated property. We currently carry environmental insurance in an amount and subject to deductibles that we believe are commercially reasonable. Specifically, we carry a pollution legal liability policy with a $10 million limit per incident and a policy aggregate limit of $25 million. 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. 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:

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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.

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 BPLP who contributed properties in exchange for partnership interests that require BPLP 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.

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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, 2004, we had approximately $424 million, and may incur more, of indebtedness that bears interest at variable rates. Accordingly, if interest rates increase, so will our interest costs, which could 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, particularly if TRIA is not extended beyond December 31, 2005.

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 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 March 4, 2005, we had approximately $5.0 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 $61.85 per share of our common stock of Boston Properties, Inc. on March 4, 2005, multiplied by the sum of (1) the actual aggregate number of outstanding common partnership units of BPLP (including common partnership units held by us), (2) the number of common partnership units available upon conversion of all outstanding preferred partnership units of BPLP and (3) the number of common units issuable upon conversion of all outstanding LTIP units assuming all conditions have been met for conversion of the LTIP units, our debt to market capitalization ratio was approximately 37.04% as of March 4, 2005.

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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 and/or difficulty in obtaining additional financing. Our degree of leverage could also make us more vulnerable to a downturn in business or the economy generally. There is a risk that changes in our debt to market capitalization ratio, which is in part a function of our stock price, or our ratio of indebtedness to other measures of asset value used by financial analysts may have an adverse effect on the market price of our equity or debt securities.

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, and the Value-Added Fund holds its 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 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.

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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 REIT 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, or proceeds from asset sales, creation of joint ventures or sales 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. The inability of our cash flows to cover our distribution requirements could have an adverse impact on our ability to raise short and long-term debt or sell equity securities in order to fund distributions required to maintain our REIT status.

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 BPLP, as well as provisions of the Internal Revenue Code and Delaware corporate law, may:

Stock Ownership Limit

To facilitate maintenance of our qualification as a REIT and to otherwise address concerns relating to concentration of capital stock ownership, 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 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.

BPLP’s Partnership Agreement

We have agreed in the limited partnership agreement of BPLP not to engage in specified extraordinary transactions, including, among others, business combinations, unless limited partners of BPLP other than Boston Properties, Inc. receive, or have the opportunity to receive, either (1) the same consideration for their partnership interests as holders of our common stock in the transaction or (2) limited partnership units that, among other things, would entitle the holders, upon redemption of these units, to receive shares of common equity of a publicly traded company or the same consideration as holders of our common stock received in the transaction. If these limited partners would not receive such consideration, we cannot engage in the transaction unless limited partners holding at least 75% of the common units of limited partnership interest, other than those held by Boston Properties, Inc. or its affiliates, consent to the transaction. In addition, we have agreed in the limited partnership agreement of BPLP that we will not complete specified extraordinary transactions, including among

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others, business combinations, in which we receive the approval of our common stockholders unless (1) limited partners holding at least 75% of the common units of limited partnership interest, other than those held by Boston Properties, Inc. or its affiliates, consent to the transaction or (2) the limited partners of BPLP are also allowed to vote and the transaction would have been approved had these limited partners been able to vote as common stockholders on the transaction. Therefore, if our common stockholders approve a specified extraordinary transaction, 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 extraordinary transaction, including a proposed business combination, even though our stockholders approve of the transaction.

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 of 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. 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 three Executive Vice Presidents 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.

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Conflicts of interest exist with holders of interests in BPLP.

Sales of properties and repayment of related indebtedness will have different effects on holders of interests in BPLP than on our stockholders.

Some holders of interests in BPLP, 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 BPLP 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 BPLP 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 BPLP, 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 BPLP, 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 BPLP. 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, 2004, there were a total of 28 properties subject to these restrictions, and those properties are estimated to have accounted for approximately 42.0% of our total revenue for the year ended December 31, 2004.

BPLP 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.

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 of 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:

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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 greater or less 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 BPLP were issued to owners of properties we acquired or to institutional investors. This common stock, or common stock issuable in exchange for such partnership interests in BPLP, may be sold in the public securities markets over time under registration rights we granted to these investors. Additional common stock issuable under our employee benefit and other incentive plans, including as a result of the grant of stock options and restricted equity securities, 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 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 or future 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, however, these policies may be for amounts less than the current or future values of the applicable properties.

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. These increased tax costs could adversely affect our financial condition and results of operations and the amount of cash available for payment of dividends.

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We face possible state and local tax audits.

Because we are organized and qualify as a REIT, we are generally not subject to federal income taxes, but are subject to certain state and local taxes. In the normal course of business, certain entities through which we own real estate either have undergone, or are currently undergoing, tax audits. Although we believe that we have substantial arguments in favor of our positions in the ongoing audits, in some instances there is no controlling precedent or interpretive guidance on the specific point at issue. Collectively, tax deficiency notices received to date from the jurisdictions conducting the ongoing audits have not been material. However, there can be no assurance that future audits will not occur with increased frequency or that the ultimate result of such audits will not have a material adverse effect on our results of operations.

At December 31, 2004, our portfolio consisted of 125 properties totaling 44.1 million net rentable square feet. Our properties consisted of (1) 119 office properties, comprised of 102 Class A office buildings, including three properties under construction and 17 properties that support both office and technical uses, (2) one industrial property, (3) two retail properties, and (4) three hotels. In addition, we own or control 543 acres of land for future development. The table set forth below shows information relating to the properties we owned, or in which we had an ownership interest, at December 31, 2004. Information relating to properties owned by the Value-Added Fund is not included in our portfolio information tables or any other portfolio level statistics because the Value-Added Fund invests in assets within our existing markets that have deficiencies in property characteristics which provide an opportunity to create value through repositioning, refurbishment or renovation and we believe including such information in our portfolio tables and statistics would render the portfolio information less useful to investors. Information relating to the Value-Added Fund is set forth below separately.

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The following table shows information relating to investments through the Value-Added Fund as of December 31, 2004:

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Top 20 Tenants by Square Feet

Lease Expirations

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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, 2004.

PART II

(a) 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: