UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

For the fiscal year ended December 31, 2007.2008.

For the Transition Period From                     to                      .

Commission file number 001-32336

DIGITAL REALTY TRUST, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code (415) 738-6500

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 the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    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 a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer and large accelerated filer” in Rule 12b-2 of the Exchange Act.

Large-accelerated filer  x    Accelerated filer  ¨    Non-accelerated filer  ¨    Small reporting company  ¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act.):    Yes  ¨    No  x

The aggregate market value of the common equity held by non-affiliates of the registrant as of June 30, 20072008 totaled approximately $2,009.8$2,400.2 million based on the closing price for the registrant’s common stock on that day as reported by the New York Stock Exchange. Such value excludes common stock held by executive officers, directors and 10% or greater stockholders as of June 30, 2007.2008. The identification of 10% or greater stockholders as of June 30, 20072008 is based on Schedule 13G and amended Schedule 13G reports publicly filed before June 30, 2007.2008. This calculation does not reflect a determination that such parties are affiliates for any other purposes.

Indicate the number of shares outstanding of each of the registrant’s classes of common stock, as of the latest practicable date.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s Proxy Statement with respect to its 20082009 Annual Meeting of Stockholders to be filed not later than 120 days after the end of the registrant’s fiscal year are incorporated by reference into Part III hereof.

DIGITAL REALTY TRUST, INC.

FORM 10-K

FOR THE YEAR ENDED DECEMBER 31, 20072008

TABLE OF CONTENTS

PART 1

General

As used herein, the terms “we,” “our,” “us,” “the company” and “our company” refer to Digital Realty Trust, Inc., a Maryland corporation, together with our consolidated subsidiaries, including Digital Realty Trust, L.P., a Maryland limited partnership of which we are the sole general partner and which we refer to as our operating partnership. We target high-quality, strategically located properties containing applications and operations critical to the day-to-day operations of technology industry tenants and corporate enterprise datacenter users, including the information technology, or IT, departments of Fortune 1000 and financial services companies. Our tenant base is diversified within the technology industry and reflects a broad spectrum of regional, national and international tenants that are leaders in their respective areas. We operate as a real estate investment trust, or REIT, for federal income tax purposes.

Through our operating partnership, at December 31, 20072008 we owned 7075 properties, excluding one property held as an investment in an unconsolidated joint venture. Our properties are primarily located throughout North America with 1213 properties in Europe. Our properties contain a total of approximately 12.313.0 million net rentable square feet, including approximately 1.81.6 million square feet held for redevelopment. A significant component of our current and future internal growth is anticipated through the development of our existing space held for redevelopment and new properties. Our operations and acquisition activities are focused on a limited number of markets where technology industry tenants and corporate datacenter users are concentrated, including the Chicago, Dallas, Los Angeles, New York,York/New Jersey, Northern Virginia, Phoenix, San Francisco and Silicon Valley metropolitan areas in the U.S. and the Amsterdam,London, Dublin, LondonParis and ParisAmsterdam markets in Europe. As of December 31, 2007,2008, our portfolio, excluding space held for redevelopment, was approximately 94.7%94.9% leased at an average annualized rent per leased square foot of $29.18.$36.09. The types of properties within our focus include:

Many of our properties have tenant improvements that have been installed at our tenants’ expense. Unlike traditional office and flex/research and development space, the location of and improvements to our facilities are generally essential to our tenants’ businesses, which we believe results in high occupancy levels, long lease terms and low tenant turnover. In addition, many of our properties have tenant improvements that have been installed at our tenants’ expense. The tenant improvements in our facilities are generally readily adaptable for use by similar tenants. We also havehad approximately 1.81.6 million square feet available for redevelopment at December 31, 2007.2008.

Our principal executive offices are located at 560 Mission Street, Suite 2900, San Francisco, California 94105. Our telephone number at that location is (415) 738-6500. Our website is located at www.digitalrealtytrust.com. The information found on, or otherwise accessible through, our website is not incorporated into, and does not form a part of, this annual report on Form 10-K or any other report or document we file with or furnish to the United States Securities and Exchange Commission, or the Securities and Exchange Commission.

Recent Developments

On December 21, 200710, 2008, we acquired Units 1, 2the remaining 50% interest in a joint venture that owns 1500 Space Park Drive and 3 of the Foxboro Business Park, a three building complex1201 Comstock Street for approximately $20.6 million. The two properties are located in suburban London, England for approximately £21.9 million ($43.6 million based on the exchange rate on December 21, 2007).Santa Clara, California. The acquisition was financed with borrowings under our revolving credit facility.

On December 12, 2007November 20, 2008, we acquired Naritaweg 52,7505 Mason King Court, a property located in Amsterdam, The NetherlandsManassas, Virginia for approximately €18.5 million ($27.2 million based on the exchange rate on December 12, 2007).$10.6 million. The acquisition was financed with borrowings under our revolving credit facility. In January 2009, we leased the entire space within the 109,650 square foot building to a single tenant.

On December 10, 2007November 5, 2008, we acquired Cressex 1,made a property located in suburban London, England for approximately £6.3draw of $33.0 million ($12.7on our Prudential Shelf Facility, or our Shelf Facility. The $33.0 million based onseries B notes have an interest-only rate of 9.32% per annum and a five-year maturity. We used the exchange rate on December 10, 2007). The acquisition was financed withproceeds of the notes to temporarily repay borrowings under our revolving credit facility.facility and for general corporate purposes.

Subsequent Events

On October 22, 2007,February 24, 2009, we declared the following distributions per share and the Operating Partnership made an equivalent distribution per unit.

On February 13, 2009, we completed an offering of 4,025,0002,500,000 shares of common stock for total net proceeds, after underwriting discounts anddeducting estimated offering expenses, of $150.4 million, including the proceeds from the exercise of the underwriters’ over-allotment option.approximately $83.3 million. We used the net proceeds from the offering to temporarily repay borrowings under our revolving credit facility, to acquire properties, to fund development and redevelopment activities and for general corporate purposes.

Subsequent Events

On February 25, 2008,January 6, 2009, we declared the following distributionsmade a draw of $25.0 million on our Shelf Facility. The $25.0 million series C notes have an interest-only rate of 9.68% per shareannum and the Operating Partnership made an equivalent distribution per unit.

On February 14, 2008 we acquired 365 South Randolphville Road, a property located in Piscataway, New Jersey for approximately $20.2 million. The acquisition was financed with borrowings under our revolving credit facility.

On February 6, 2008, we issued 13.8 million shares of 5.500% series D cumulative convertible preferred stock for total net proceeds, after underwriting discounts and estimated offering expenses, of approximately $333.6 million, includingseven-year maturity. We intend to use the proceeds from the exercise of the underwriters’ over-allotment option. We used the net proceeds from the offeringnotes to temporarily repay borrowings under our revolving credit facility to acquire properties, to fund redevelopment activities and for general corporate purposes.

On January 30, 2008,February 27, 2009, we amendednotified the lenders under our chartermortgage agreement with respect to increase350 East Cermak Road that we will repay in full the number of authorized shares ofoutstanding principal balance, accrued interest and other fees due on the loan on March 9, 2009. We expect to finance the repayment with approximately $97.0 million in borrowings under our common stock, $0.01 par value per share, available for issuance from 100,000,000 to 125,000,000 and the number of authorized shares of our preferred stock, $0.01 par value per share, available for issuance from 20,000,000 to 30,000,000.revolving credit facility.

Our Competitive Strengths

We believe we distinguish ourselves from other owners, acquirors and managers of technology-related real estate through our competitive strengths, which include:

Internet gateway datacenter facilities is equipped to meet the power and cooling requirements for the most demanding corporate IT applications. Many of the properties in our portfolio are located on major aggregation points formed by the physical presence of multiple major telecommunications service providers, which reduces our tenants’ costs and operational risks and increases the attractiveness of our buildings.

•

Development Advantages.Our extensive development activity, operating scale and process-based approach to datacenter design, construction and operations can result in significant cost savings and added value for our tenants. We have leveraged our purchasing power by securing global purchasing agreements and developing relationships with major equipment manufacturers, reducing costs and shortening delivery timeframes on key components, including major mechanical and electrical equipment. Utilizing our innovative modular datacenter design, referredwhich we refer to as POD Architecture ™SM, we deliver what we believe to be a technically superior datacenter environment at significant cost savings. In addition, by utilizing our POD Architecture ™SM to develop new Turn-Key Datacenters ™SM in our existing Powered Base Buildings ™SM, on average we have been able to deliver a fully commissioned

facility in just under 30 weeks. Finally, our access to capital allows us to provide financing options for tenants that do not want to invest their own capital.

Business and Growth Strategies

Our primary business objectives are to maximize sustainable long-term growth in earnings, funds from operations and cash flow per share and to maximize returns to our stockholders. Our business strategies to achieve these objectives are:

Competition

We compete with numerous developers, owners and operators of real estate and datacenters, many of which own properties similar to ours in the same markets in which our properties are located, including DuPont Fabros Technology, Inc., 365 Main Inc., Equinix, Inc.CRG West and various local developers in the U.S., and Global Switch Equinix, Inc. and various regional operators in Europe. If our competitors offer space that our tenants or potential tenants perceive to be superior to ours based on numerous factors, including available power, security considerations, location, or connectivity, or if they offer rental rates below current market rates, or below the rental rates we are offering, we may lose tenants or potential tenants or be required to incur costs to improve our properties or reduce our rental rates. In addition, recently many of our competitors have developed or redeveloped additional datacenter space. If the supply of datacenter space continues to increase as a result of these activities or otherwise, rental rates may be reduced or we may face delays in or be unable to lease our vacant space, including space that we develop or redevelop. Finally, if tenants or potential tenants desire services that we do not offer, we may not be able to lease our space to those tenants. Our financial condition, results of operations, cash flow, cash available for distribution, including cash available to pay dividends to our preferred or common stockholders, and ability to satisfy our debt service obligations could be materially adversely affected as a result of any or all of these factors.

Regulation

General

Office properties in our submarkets are subject to various laws, ordinances and regulations, including regulations relating to common areas. We believe that each of our properties as of December 31, 20072008 has the necessary permits and approvals to operate its business.

Americans With Disabilities Act

Our properties must comply with Title III of the Americans with Disabilities Act of 1990, or the ADA, to the extent that such properties are “public accommodations” as defined by the ADA. The ADA may require

removal of structural barriers to access by persons with disabilities in certain public areas of our properties where such removal is readily achievable. We believe that our properties are in substantial compliance with the ADA and that we will not be required to make substantial capital expenditures to address the requirements of the ADA. However, noncompliance with the ADA could result in imposition of fines or an award of damages to private litigants. The obligation to make readily achievable accommodations is an ongoing one, and we will continue to assess our properties and to make alterations as appropriate in this respect.

Environmental Matters

Under various laws relating to the protection of the environment, a current or previous owner or operator of real estate may be liable for contamination resulting from the presence or discharge of hazardous or toxic substances at that property, and may be required to investigate and clean up such contamination at that property or emanating from that property. Such laws often impose liability without regard to whether the owner or operator knew of, or was responsible for, the presence of the contaminants, and the liability may be joint and several. Previous owners used some of our properties for industrial and retail purposes, so those properties may contain some level of environmental contamination. The presence of contamination or the failure to remediate contamination at our properties may expose us to third-party liability or materially adversely affect our ability to sell, lease or develop the real estate or to borrow using the real estate as collateral.

Some of the properties may contain asbestos-containing building materials. Environmental laws require that asbestos-containing building materials be properly managed and maintained, and may impose fines and penalties on building owners or operators for failure to comply with these requirements. These laws may also allow third parties to seek recovery from owners or operators for personal injury associated with exposure to asbestos-containing building materials.

In addition, some of our tenants, particularly those in the biotechnology and life sciences industry and those in the technology manufacturing industry, routinely handle hazardous substances and wastes as part of their operations at our properties. Environmental laws and regulations subject our tenants, and potentially us, to liability resulting from these activities or from previous industrial or retail uses of those properties. Environmental liabilities could also affect a tenant’s ability to make rental payments to us. We require our tenants to comply with these environmental laws and regulations and to indemnify us for any related liabilities.

Independent environmental consultants have conducted Phase I or similar environmental site assessments on all of the properties in our portfolio. Site assessments are intended to discover and evaluate information regarding the environmental condition of the surveyed property and surrounding properties. These assessments do not generally include soil samplings, subsurface investigations or an asbestos survey. None of the recent site assessments revealed any past or present environmental liability that we believe would have a material adverse effect on our business, assets or results of operations. However, the assessments may have failed to reveal all environmental conditions, liabilities or compliance concerns. Material environmental conditions, liabilities or compliance concerns may have arisen after the review was completed or may arise in the future; and future laws, ordinances or regulations may impose material additional environmental liability.

Insurance

We carry comprehensive liability, fire, extended coverage, earthquake, business interruption and rental loss insurance covering all of the properties in our portfolio under a blanket policy. We select policy specifications and insured limits which we believe to be appropriate given the relative risk of loss, the cost of the coverage and industry practice and, in the opinion of our company’s management, the properties in our portfolio are currently adequately insured. We do not carry insurance for generally uninsured losses such as loss from war, or nuclear reaction. In addition, we carry earthquake insurance on our properties in an amount and with deductibles which we believe are commercially reasonable. Certain of the properties in our portfolio are located in areas known to be seismically active. See “Risk Factors—Risks Related to Our Business and Operations—Potential losses may not be covered by insurance.”

Employees

As of December 31, 20072008 we had 153210 employees. None of these employees is represented by a labor union.

Offices

Our headquarters is located in San Francisco. We have regional offices in Boston, Chicago, Dallas, Los Angeles, New York, Northern Virginia and Phoenix and international offices in Dublin, London and Paris.

For purposes of this section, the term “stockholders” means the holders of shares of our common stock and of our preferred stock. Set forth below are the risks that we believe are material to our stockholders. You should carefully consider the following factors in evaluating our company, our properties and our business. The occurrence of any of the following risks might cause our stockholders to lose all or a part of their investment. Some statements in this report including statements in the following risk factors constitute forward-looking statements. Please refer to the section entitled “Forward-Looking Statements” starting on page 26.27.

Risks Related to Our Business and Operations

Global Economic Conditions

Recent U.S., European and other international market and economic conditions have been unprecedented and challenging, with significantly tighter credit conditions and recession in all markets in which we own properties and conduct our operations continuing into 2009. Continued concerns about the systemic impact of potential wide-spread and long-term recession, energy costs, geopolitical issues, the availability and cost of credit, global financial and mortgage markets, corporate and consumer debt levels and declining residential and commercial real estate markets have contributed to increased market volatility and diminished expectations for the U.S., European and other economies. In the second half of 2008, added concerns fueled by the U.S. government’s conservatorship of the Federal Home Loan Mortgage Corporation and the Federal National Mortgage Association, the forced sale of Bear Stearns to JPMorgan Chase, the declared bankruptcy of Lehman Brothers Holdings Inc., the U.S. government’s financial assistance to American International Group Inc., Citibank, Bank of America and other federal government interventions in the U.S. financial system and similar events in Europe and other regions has led to increased uncertainty and instability in global capital and credit markets. These conditions, combined with volatile oil prices, declining business and consumer confidence and increased unemployment have and continue to contribute to global volatility of unprecedented levels.

As a result of these conditions, general economic conditions and the cost and availability of capital have been and may continue to be adversely affected in all markets in which we own properties and conduct our operations. Concern about the stability of the markets generally and the strength of counterparties specifically has led many lenders and institutional investors to reduce, and in some cases, cease, to provide credit to businesses and consumers. Continued turbulence in the U.S., European and other international markets and economies may adversely affect our liquidity and financial condition, and the liquidity and financial condition of our tenants. If these market and economic conditions continue, they may limit our ability, and the ability of our tenants, to replace or renew maturing liabilities on a timely basis, access the capital markets to meet liquidity and capital expenditure requirements and may result in adverse effects on our, and our tenants’, financial condition and results of operations.

In addition, our access to funds under our revolving credit facility and other lines of credit depend on the ability of the lenders that are parties to such facilities to meet their funding commitments to us. We cannot assure you that continuing long-term disruptions in the global economy and the continuation of tighter credit conditions among, and potential failures or nationalizations of, third party financial institutions as a result of such disruptions will not have an adverse effect on our lenders. If our lenders are not able to meet their funding commitments to us, our business, results of operation, cash flows and financial condition could be adversely affected.

If we do not have sufficient cash flow to continue operating our business and are unable to borrow additional funds, access our existing lines of credit or raise equity capital, we may need to find alternative ways to increase our liquidity. Such alternatives may include, without limitation, curtailing development or redevelopment activity, disposing of one or more of our properties possibly on disadvantageous terms or entering into or renewing leases on less favorable terms than we otherwise would.

Our growth depends on external sources of capital which are outside of our control.

In order to maintain our qualification as a REIT, we are required under the Code to annually distribute at least 90% of our net taxable income, determined without regard to the dividends paid deduction and excluding any net capital gain. In addition, we will be subject to income tax at regular corporate rates to the extent that we distribute less than 100% of our net taxable income, including any net capital gains. Because of these distribution requirements, we may not be able to fund future capital needs, including any necessary acquisition or redevelopment financing, from operating cash flow. Consequently, we rely on third-party sources to fund our capital needs. We may not be able to obtain equity or debt financing on favorable terms or at all. Any additional debt we incur will increase our leverage. Our access to third-party sources of capital depends, in part, on:

If the United States Federal Reserve increases short term interest rates, this would have a significant upward impact on shorter-term interest rates, including the interest rates that our variable rate debt is based upon. Furthermore, difficulties with “sub-prime” residential housing credit have impacted corporate debt. Liquidity previously provided by commercial mortgage-backed securities and collateralized debt obligations has significantly decreased. The affects on commercial real estate mortgages and other debt include:

There is no assurance that we will be able to obtain debt financing at all or on terms favorable or acceptable to us.

Potential future increases in interest rates and credit spreads may increase our interest expense and therefore negatively affect our financial condition, results of operations, and reduce our access to capital markets. Increased interest rates may also increase the risk that the counterparties to our swap agreements will default on their obligations, which would further increase our interest expense. Equity markets have experienced high volatility recently and there is no assurance that we will be able to raise capital through the sale of equity securities at all or on favorable terms. Sales of equity on unfavorable terms could result in substantial dilution to our common stockholders.

If we cannot obtain capital from third-party sources, we may not be able to acquire or develop properties when strategic opportunities exist, satisfy our debt service obligations or pay cash dividends to our stockholders to maintain our qualification as a REIT.

Declining real estate valuations and impairment charges could adversely affect our earnings and financial condition.

We review the carrying value of our properties when circumstances, such as adverse market conditions (including conditions resulting from the current global economic recession), indicate potential impairment may exist. We base our review on an estimate of the future cash flows (excluding interest charges) expected to result

from the real estate investment’s use and eventual disposition. We consider factors such as future operating income, trends and prospects, as well as the effects of leasing demand, competition and other factors. If our evaluation indicates that we may be unable to recover the carrying value of a real estate investment, an impairment loss is recorded to the extent that the carrying value exceeds the estimated fair value of the property. These losses have a direct impact on our net income because recording an impairment loss results in an immediate negative adjustment to net income. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. A worsening real estate market may cause us to reevaluate the assumptions used in our impairment analysis. Impairment charges could adversely affect our financial condition, results of operations, cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders and per share trading price of our common stock or preferred stock.

Our properties depend upon the demand for technology-related real estate.

Our portfolio of properties consists primarily of technology-related real estate, and datacenter real estate in particular. A decrease in the demand for datacenter space, Internet gateway facilities or other technology-related real estate would have a greater adverse effect on our business and financial condition than if we owned a portfolio with a more diversified tenant base or less specialized use. Our substantial redevelopment activities make us particularly susceptible to general economic slowdowns, including recessions, as well as adverse developments in the corporate datacenter, Internet and data communications and broader technology industries. Any such slowdown or adverse development could lead to reduced corporate IT spending or reduced demand for datacenter space. Reduced demand could also result from business relocations, including to markets that we do not currently serve such as Asia. Changes in industry practice or in technology, such as virtualization technology, more efficient computing or networking devices, or devices that require higher power densities than today’s devices, could also reduce demand for the physical datacenter space we provide or make the tenant improvements in our facilities obsolete or in need of significant upgrades to remain viable. In addition, the development of new technologies, the adoption of new industry standards or other factors could render many of our tenants’ current products and services obsolete or unmarketable and contribute to a downturn in their businesses, thereby increasing the likelihood that they default under their leases, become insolvent or file for bankruptcy.

We depend on significant tenants, and many of our properties are single-tenant properties or are currently occupied by single tenants.

As of December 31, 2007,2008, the 1520 largest tenants in our property portfolio represented approximately 51%57% of the total annualized rent generated by our properties. Our largest tenants by annualized rent are Savvis Communications and Qwest Communications International. Savvis Communications leased approximately 1.61.7 million square feet of net rentable space as of December 31, 2007,2008, representing approximately 11.8%11.1% of the total annualized rent generated by our properties. Qwest Communications International leased approximately 771,000638,000 square feet of net rentable space as of December 31, 2007,2008, representing approximately 8.2%5.1% of the total annualized rent generated by our properties. In addition, 3135 of our 7075 properties are occupied by single tenants, including properties occupied solely by Savvis Communications and Qwest Communications International. OurMany factors, including consequences of current global economic conditions, may cause our tenants mayto experience a downturn in their businesses or otherwise experience a lack of liquidity, which may weaken their financial condition and result in their failure to make timely rental payments or their default under their leases. If any tenant defaults or fails to make timely rent payments, we may experience delays in enforcing our rights as landlord and may incur substantial costs in protecting our investment.

The bankruptcy or insolvency of a major tenant may adversely affect the income produced by our properties.

If any tenant becomes a debtor in a case under the federal Bankruptcy Code, we cannot evict the tenant solely because of the bankruptcy. In addition, the bankruptcy court might authorize the tenant to reject and terminate its lease with us. Our claim against the tenant for unpaid, future rent would be subject to a statutory cap that might be substantially less than the remaining rent actually owed under the lease. In either case, our claim for unpaid rent would likely not be paid in full. At December 31, 2007, we had no significant tenants2008 one tenant, Lyondell Chemical Company (Lyondell) was in bankruptcy, however, there can be no assurance that no significant tenant will enter into bankruptcybankruptcy. As of December 31, 2008, Lyondell leased approximately 15,500 square feet of net rentable space at a property in the future.Dallas, Texas and was current on all of its rental obligations.

Our revenue and cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, including us, could be materially adversely affected if any of our significant tenants were to become bankrupt or insolvent, or suffer a downturn in its business, or fail to renew its lease or renew on terms less favorable to us than its current terms.

Our portfolio of properties depends upon local economic conditions and is geographically concentrated in certain locations.

Our properties are located in 2627 metropolitan areas. We depend upon the local economic conditions in these markets, including local real estate conditions. Many of these markets experienced downturns in recent years and either are currently or may experienceexperiencing downturns inas a result of the near future.global economic crisis. Our operations may also be affected if too many competing properties are built in any of these markets or supply otherwise increases or exceeds demand. If there is a downturn in the economy in any of these markets, ourOur operations and our revenue and cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, including us, could be materially adversely affected.affected by the global economic downturn. We cannot assure you that these markets will grow or will remain favorable to technology-related real estate.

In addition, ourOur portfolio is geographically concentrated in the following metropolitan markets.

In addition, we are currently developing or redeveloping properties in certain of these markets, as well as in Dublin, London Northern Virginia and Paris. Any further negative changes in real estate, technology or economic conditions in these markets in particular could negatively impact our performance.

Our growth depends upon the successful development of our existing space held for redevelopment and new properties acquired for redevelopment and any delays or unexpected costs in such development or difficulties in leasing or operating newly developed space may delay and harm our growth prospects, future operating results and financial condition.

A significant component of our current and future internal growth is anticipated through the development of our existing spaceWe had approximately 1.6 million square feet held for redevelopment at December 31, 2008, including four vacant buildings. We are and new properties acquired for redevelopment.intend to continue building out a large portion of this space on a speculative basis at significant cost. Our successful development and redevelopment of these projects depends onis subject to many risks, including those associated with:

In addition, development and redevelopment activities, regardless of whether they are ultimately successful, typically require a substantial portion of management’s time and attention. This may distract management from focusing on other operational activities. If we are unable to complete development or redevelopment projects successfully, our business may be adversely affected.

We may be unable to successfully complete and operate developed properties.

We intend to develop and substantially renovate properties for data center use. Our future development and construction activities involve the following significant risks:

In addition, in certain circumstance we lease data center facilities prior to their completion. If we fail to complete the facilities in a timely manner, the tenant may be entitled to terminate theirits lease, seek damages or penalties against us or pursue other remedies.

While we intend to develop data center properties primarily in markets we are familiar with, we may in the future develop properties in new geographic regions where we expect the development of property to result in favorable risk-adjusted returns on our investment. We may not possess the same level of familiarity with development of other property types or other markets, which could adversely affect our ability to develop such properties successfully or at all or to achieve expected performance.

WeDevelopment and redevelopment activities, regardless of whether they are ultimately successful, typically require a substantial portion of management’s time and attention. This may encounter problems during development and constructiondistract management from focusing on other operational activities.

We If we are currently developing data centers in multiple locations. These construction projects, and others that we may undertake from time to time, are subject to significant development and construction risks, any of which could cause unanticipated cost increases and delays. These include the following:

We may not be ableunable to complete the development of anyor redevelopment projects we begin and, if completed,successfully, our development and construction activitiesbusiness may not be completed in a timely manner or within budget, which could have a material adverse effect on our results of operations and prospects. If any of these factors result in a delay in the completion of or our inability to complete a project, or increase our costs associated with development, our financial performance could be materially adversely affected.

We have owned certain of our properties for a limited time.

We owned 7075 properties at December 31, 2007,2008, excluding one property held as an investment in an unconsolidated joint venture. These properties are primarily located throughout North America and 1213 properties are located in Europe. The properties contain a total of approximately 12.313.0 million net rentable square feet, including 1.81.6 million square feet held for redevelopment. All the properties have been under our management for less than five years, and we have owned 13five of the properties for less than one year at December 31, 2007.2008. The properties may have characteristics or deficiencies unknown to us that could affect their valuation or revenue potential. We cannot assure you that the operating performance of the properties will not decline under our management. In addition, we have a limited history operating Turn-Key Datacenters^™SM that we have developed or redeveloped. Because we generally cannot pass operating expenses (other than energy costs) on to our tenants in Turn-Key Datacenters^™SM, if we incur operating expenses greater than we anticipated based on our limited operating history, our results of operations could be negatively impacted.

We have space available for redevelopment that may be difficult to redevelop or successfully lease to tenants.

We have approximately 1.8 million square feet held for redevelopment at December 31, 2007 including eight vacant buildings. Successful redevelopment of this space depends on numerous factors including success in engaging contractors, obtaining permits, securing key components and availability of financing. We are and

intend to continue building out a large portion of this space on a speculative basis at significant cost. In addition we cannot assure you that once completed we will be able to successfully lease redeveloped space to new or existing tenants at all, or at rates we consider favorable or expected at the time we commenced redevelopment. If we are not able to lease redevelopment space, or lease it at rates below those we expected to achieve when we started the project, our financial performance would be materially adversely affected.

We may have difficulty managing our growth.

We have significantly expanded the size of our company. For example, during 2007,2008, we acquired 13five properties, including five propertiesone property outside the United States, our number of employees increased from 109153 to 153210 and we substantially increased the number and size of our redevelopment activities. The growth in our company may significantly strain our management, operational and financial resources and systems. In addition, as a public company, we are subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, or the Exchange Act, the Sarbanes-Oxley Act of 2002, or the Sarbanes-Oxley Act, and the rules and regulations of the NYSE. The requirements of these rules and regulations have increased our accounting, legal and financial compliance costs and may strain our management and financial, legal and operational resources and systems. An inability to manage our growth effectively or the increased strain on management of our resources and systems could result in deficiencies in our disclosure controls and procedures or our internal control over financial reporting and could negatively impact our cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, including us.

We have limited operating history as a REIT and as a public company.

We were formed in March 2004 and have limited operating history as a REIT and as a public company. We cannot assure you that our past experience will be sufficient to successfully operate our company as a REIT or as a public company. Failure to maintain REIT status or failure to meet the requirements of being a public company would have an adverse effect on our cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, including us.

Tax protection provisions on certain properties could limit our operating flexibility.

We have agreed with the third-party contributors who contributed the direct and indirect interests in the 200 Paul Avenue 1-4 and 1100 Space Park Drive properties to indemnify them against adverse tax consequences if we were to sell, convey, transfer or otherwise dispose of all or any portion of these interests, in a taxable transaction, in these properties. However, we can sell these properties in a taxable transaction if we pay the contributors cash in the amount of their tax liabilities arising from the transaction and tax payments. The 200 Paul Avenue 1-4 and 1100 Space Park Drive properties represented 9.0%7.8% of our portfolio’s annualized rent as of December 31, 2007.2008. These tax protection provisions apply for a period expiring on the earlier of November 3, 2013 and the date on which these contributors (or certain transferees) hold less than 25% of the units issued to them in connection with the contribution of these properties to our operating partnership. Although it may be in our stockholders’ best interest that we sell a property, it may be economically disadvantageous for us to do so because of these obligations. We have also agreed to make up to $17.8 million of debt available for these contributors to guarantee. We agreed to these provisions in order to assist these contributors in preserving their tax position after their contributions.

Potential losses may not be covered by insurance.

We carry comprehensive liability, fire, extended coverage, earthquake, business interruption and rental loss insurance covering all of the properties in our portfolio under various insurance policies. We select policy specifications and insured limits which we believe to be appropriate and adequate given the relative risk of loss, the cost of the coverage and industry practice. We do not carry insurance for generally uninsured losses such as

loss from riots, terrorist threats, war or nuclear reaction. Most of our policies, like those covering losses due to floods, are insured subject to limitations involving large deductibles or co-payments and policy limits which may not be sufficient to cover losses. A large portion of the properties we own are located in California, an area especially subject to earthquakes. Together, these properties represented approximately 28%26% of our portfolio’s annualized rent as of December 31, 2007.2008. While we carry earthquake insurance on our properties, the amount of our earthquake insurance coverage may not be sufficient to fully cover losses from earthquakes. In addition, we may discontinue earthquake or other insurance on some or all of our properties in the future if the cost of premiums for any of these policies exceeds, in our judgment, the value of the coverage relative to the risk of loss.

In addition, many of our buildings contain extensive and highly valuable technology-related improvements. Under the terms of our leases, tenants generally retain title to such improvements and are obligated to maintain adequate insurance coverage applicable to such improvements and under most circumstances use their insurance proceeds to restore such improvements after a casualty. In the event of a casualty or other loss involving one of our buildings with extensive installed tenant improvements, our tenants may have the right to terminate their leases if we do not rebuild the base building within prescribed times. In such cases, the proceeds from tenants’ insurance will not be available to us to restore the improvements, and our insurance coverage may be insufficient to replicate the technology-related improvements made by such tenants. Furthermore, the terms of our mortgage indebtedness at certain of our properties may require us to pay insurance proceeds over to our lenders under certain circumstances, rather than use the proceeds to repair the property.

If we or one or more of our tenants experiences a loss which is uninsured or which exceeds policy limits, we could lose the capital invested in the damaged properties as well as the anticipated future cash flows from those properties. In addition, if the damaged properties are subject to recourse indebtedness, we would continue to be liable for the indebtedness, even if these properties were irreparably damaged.

Payments on our debt reduce cash available for distribution and may expose us to the risk of default under our debt obligations.

Our total consolidated indebtedness at December 31, 20072008 was approximately $1.4 billion, and we may incur significant additional debt to finance future acquisition and development activities. We have a revolving credit facility, which has a borrowing limit based upon a percentage of the value of our unsecured properties included in the facility’s borrowing base. At December 31, 2007, $299.72008, $524.0 million was available under this facility. In addition, under our contribution agreement with respect to the 200 Paul Avenue 1-4 and 1100 Space Park Drive properties, we have agreed to make available for guarantee up to $17.8 million of indebtedness and may enter into similar agreements in the future.

Payments of principal and interest on borrowings may leave us with insufficient cash resources to operate our properties, for our operating partnership to pay distributions to its unitholders, including us, and, consequently, for us to pay cash dividends to our stockholders that are necessary to maintain our REIT qualification. Our level of debt and the limitations imposed on us by our debt agreements could have significant adverse consequences, including the following:

If any one of these events were to occur, our financial condition, results of operations, cash flow, cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, per share trading price of our common stock or preferred stock, and our ability to satisfy our debt service obligations could be materially adversely affected. Furthermore, foreclosures could create taxable income without accompanying cash proceeds, a circumstance which could hinder our ability to meet the REIT distribution requirements imposed by the Internal Revenue Code of 1986, as amended, which we refer to as the Code.

We may be unable to identify and complete acquisitions and successfully operate acquired properties.

We continually evaluate the market of available properties and may acquire additional technology-related real estate when opportunities exist. Our ability to acquire properties on favorable terms and successfully operate them may be exposed to the following significant risks:

If we cannot finance property acquisitions on favorable terms, or operate acquired properties to meet our financial expectations, our financial condition, results of operations, cash flow, cash available for distribution,

including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, per share trading price of our common stock or preferred stock, and ability to satisfy our debt service obligations could be materially adversely affected.

We may be unable to source off-market deal flow in the future.

A key component of our growth strategy is to continue to acquire additional technology-related real estate. To date, more than half of our acquisitions were acquired before they were widely marketed by real estate brokers, or “off-market.” Properties that are acquired off-market are typically more attractive to us as a purchaser because of the absence of competitive bidding, which could potentially lead to higher prices. We obtain access to off-market deal flow from numerous sources. If we cannot obtain off-market deal flow in the future, our ability to locate and acquire additional properties at attractive prices could be adversely affected.

We face significant competition, which may decrease or prevent increases of the occupancy and rental rates of our properties.

We compete with numerous developers, owners and operators of real estate and datacenters, many of which own properties similar to ours in the same markets in which our properties are located, including DuPont Fabros Technology, Inc., 365 Main Inc., Equinix, Inc.CRG West and various local developers in the U.S., and Global Switch Equinix, Inc. and various regional operators in Europe. In addition, we may in the future face competition from new entrants into the datacenter market, including new entrants who may acquire our current competitors. Some of our competitors and potential competitors have significant advantages over us, including greater name recognition, longer operating histories, pre-existing relationships with current or potential customers, significantly greater financial, marketing and other resources and more ready access to capital which allow them to respond more quickly to new or changing opportunities. If our competitors offer space that our tenants or potential tenants perceive to be superior to ours based on numerous factors, including available power, security considerations, location, or connectivity, or if they offer rental rates below current market rates, or below the rental rates we are offering, we may lose tenants or potential tenants or be required to incur costs to improve our properties or reduce our rental rates. In addition, recently many of our competitors have developed or redeveloped additional datacenter space. If the supply of datacenter space continues to increase as a result of these activities or otherwise, rental rates may be reduced or we may face delays in or be unable to lease our vacant space, including space that we develop or redevelop. Finally, if tenants or potential tenants desire services that we do not offer, we may not be able to lease our space to those tenants. Our financial condition, results of operations, cash flow, cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, and ability to satisfy our debt service obligations could be materially adversely affected as a result of any or all of these factors.

We may be unable to renew leases, re-lease space as leases it expiresexpire or lease vacant or redevelopment space.

As of December 31, 2007,2008, leases representing 8.1%12.7% of the square footage of the properties in our portfolio, excluding space held for redevelopment, were scheduled to expire through 2009,2010, and an additional 5.3%5.1% of the net rentable square footage excluding space held for redevelopment was available to be leased. Some of this space may require substantial capital investment for it to meet the power and cooling requirements of today’s advanced data centers, or may no longer be suitable for this use. In addition, we cannot assure you that leases will be renewed or that our properties will be re-leased at all, or at net effective rental rates equal to or above the current average net effective rental rates. If the rental rates for our properties decrease, our existing tenants do not renew their leases, we do not re-lease our available space, including newly redeveloped space and space for which leases are scheduled to expire or it takes longer for us to lease or re-lease this space or for rents to commence on this space, our financial condition, results of operations, cash flow, cash available for distribution,

including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, per share trading price of our common stock or preferred stock, and our ability to satisfy our debt service obligations could be materially adversely affected.

In addition, at December 31, 2007,2008, we owned approximately 1.81.6 million square feet held for redevelopment. Of this space, we are currently redeveloping 637,000409,000 square feet. We intend to continue to add new space to our redevelopment inventory and to continue to redevelop additional space from this inventory. A substantial portion of the space that we redevelop is, and will continue to be, redeveloped on a speculative basis, meaning that we do not have a signed lease for the space when we begin the redevelopment process. We also develop or redevelop space specifically for tenants pursuant to leases signed prior to beginning the development or redevelopment process. In those cases, if we failed to meet our development or redevelopment obligations under those leases, these tenants may be able to terminate the leases and we would be required to find a new tenant for this space. We cannot assure you that once we have redeveloped a space we will be able to successfully lease it. If we are not able to successfully lease the space that we redevelop, if redevelopment costs are higher than we currently estimate, or if we lease rates are lower than we expected when we began the project or are otherwise undesirable, our revenue and operating results could be adversely effected.

Our growth depends on external sources of capital which are outside of our control.

In order to maintain our qualification as a REIT, we are required under the Code to annually distribute at least 90% of our net taxable income, determined without regard to the dividends paid deduction and excluding any net capital gain. In addition, we will be subject to income tax at regular corporate rates to the extent that we distribute less than 100% of our net taxable income, including any net capital gains. Because of these distribution requirements, we may not be able to fund future capital needs, including any necessary acquisition or redevelopment financing, from operating cash flow. Consequently, we rely on third-party sources to fund our capital needs. We may not be able to obtain equity or debt financing on favorable terms or at all. Any additional debt we incur will increase our leverage. Our access to third-party sources of capital depends, in part, on:

Since 2002, with the exception of recent rate cuts, the United States Federal Reserve has been increasing short term interest rates, which has had a significant upward impact on shorter-term interest rates, including the interest rates that our variable rate debt is based upon. Furthermore, difficulties with “sub-prime” residential housing credit have impacted corporate debt. Liquidity traditionally provided by collateralized debt obligations has significantly decreased. The affects on commercial real estate mortgages and other debt include:

There is no assurance that we will be able to obtain debt financing at all or on terms favorable or acceptable to us.

Potential future increases in interest rates and credit spreads may increase our interest expense and therefore negatively affect our financial condition, results of operations, and reduce our access to capital markets. Increased interest rates may also increase the risk that the counterparties to our swap agreements will default on their obligations, which would further increase our interest expense. Equity markets have experienced high volatility recently and there is no assurance that we will be able to raise capital through the sale of equity

securities at all or on favorable terms. Sales of equity on unfavorable terms could result in substantial dilution to our common stockholders.

If we cannot obtain capital from third-party sources, we may not be able to acquire or develop properties when strategic opportunities exist, satisfy our debt service obligations or pay dividends to our stockholders necessary to maintain our qualification as a REIT.affected.

Our revolving credit facility restricts our ability to engage in some business activities.

Our revolving credit facility contains negative covenants and other financial and operating covenants that, among other things:

These restrictions could cause us to default on our revolving credit facility or negatively affect our operations, our ability to pay cash dividends to our stockholders or our operating partnership’s ability to pay distributions to its unitholders, including us.

The exchange and repurchase rights of our exchangeable debentures may be detrimental to holders of common stock.

Our operating partnership has $172.5 million principal amount of 4.125% Exchangeable Senior Debentures due 2026, which we refer to as the exchangeable debentures. The exchangeable debentures may under certain circumstances be exchanged for cash (up to the principal amount of the exchangeable debentures) and, with respect to any excess exchange value, into cash, shares of our common stock or a combination of cash and shares of our common stock at an initial exchange rate of 30.6828 shares per $1,000 principal amount of exchangeable debentures. At the initial exchange rate, the exchangeable debentures are exchangeable for our common stock at an exchange price of approximately $32.5916 per share. The exchange rate of the exchangeable debentures is subject to adjustment for certain events, including, but not limited to, certain dividends on our common stock in excess of $0.265 per share per quarter, the issuance of certain rights, options or warrants to holders of our common stock, subdivisions or combinations of our common stock, certain distributions of assets, debt securities, capital stock or cash to holders of our common stock and certain tender or exchange offers. The exchangeable debentures are redeemable at the Company’s option for cash at any time on or after August 18, 2011 and are subject to repurchase for cash at the option of the holder on August 15 in the years 2011, 2016 and 2021, or upon the occurrence of certain events. The exchangeable debentures are our senior unsecured and unsubordinated obligations.

The exchange of exchangeable debentures for our common stock at a time when our common stock is trading above the exchange price would dilute stockholder ownership in our company, and could adversely affect the market price of our common stock and could impair our ability to raise capital through the sale of additional equity securities. Any adjustments to the exchange rate of the exchangeable debentures would exacerbate their dilutive effect. If the exchangeable debentures are not exchanged, the repurchase rights of holder of the exchangeable debentures may discourage or impede transactions that might otherwise be in the interest of holders of common stock. Further, these exchange or repurchase rights might be triggered in situations where we need to conserve our cash reserves, in which event such repurchase might adversely affect us and our stockholders.

The conversion rights of our convertible preferred stock may be detrimental to holders of common stock.

We have 7,000,000 shares of 4.375% series C cumulative convertible preferred stock, or the series C preferred stock, and 13,800,000 shares of 5.500% series D cumulative convertible preferred stock, or the series D preferred stock, outstanding. The series C preferred stock and the series D preferred stock may be converted into shares of our common stock subject to certain conditions. The initial conversion rate for the series C preferred stock is 0.5164 shares of our common stock per $25.00 liquidation preference, which is equivalent to an initial conversion price of $48.41 per share of our common stock. The initial conversion rate for the series D preferred stock is 0.5955 shares of our common stock per $25.00 liquidation preference, which is equivalent to an initial conversion price of $41.98 per share of our common stock. The conversion rates for the series C preferred stock and the series D preferred stock are subject to adjustment upon the occurrence of specified events, including, but not limited to, increases in dividends on our common stock, the issuance of certain rights, options or warrants to holders of our common stock, subdivisions or combinations of our common stock, certain distributions of assets, debt securities, capital stock or cash to holders of our common stock and certain tender or exchange offers.

In addition, on or prior to April 10, 2014 (in the case of the series C preferred stock) or February 6, 2015 (in the case of the series D preferred stock) in the event of a fundamental change when the applicable price of our common stock is less than $40.34 per share (in the case of the series C preferred stock) or $35.73 per share (in the case of the series D preferred stock), then holders of shares of the series C preferred stock and the series D preferred stock will have a special right to convert some or all of their series of preferred stock into a number of shares of our common stock per $25.00 liquidation preference equal to such liquidation preference, plus an amount equal to accrued and unpaid dividends to, but not including, the fundamental change conversion date, divided by 98% of the market price of our common stock. In the event that holders of shares of our preferred stock exercise this special conversion right, we have the right to repurchase for cash all or any part of preferred stock as to which the conversion right was exercised at a repurchase price equal to 100% of the liquidation preference of the preferred stock to be repurchased plus an amount equal to accrued and unpaid dividends to, but not including, the fundamental change conversion date.

The conversion of the series C preferred stock or the series D preferred stock for our common stock would dilute stockholder ownership in our company, and could adversely affect the market price of our common stock and could impair our ability to raise capital through the sale of additional equity securities. Any adjustments to the conversion rates of the series C preferred stock and the series D preferred stock would exacerbate their dilutive effect. Further, the fundamental change conversion rights might be triggered in situations where we need to conserve our cash reserves, which may limit our ability to repurchase the shares of preferred stock in lieu of conversion.

The accounting method for convertible debt securities, like our outstanding 4.125% exchangeable senior debentures, is subject to uncertainty.

The accounting for convertible securities is subject to frequent scrutiny by the accounting regulatory bodies and is subject to change. We cannot predict if or when any such change could be made and any such change could have an adverse impact on our reported or future financial results. Any such impacts could adversely affect the trading prices of our common and preferred stock.

For example, the accounting method for net share settled convertible securities, which would include our outstanding 4.125% exchangeable senior debentures, has been under review by the accounting regulatory bodies for some time. Under the current accounting rules, for the purpose of calculating diluted earnings per share, a net share settled convertible security meeting certain requirements is accounted for in a manner similar to nonconvertible debt, with the stated coupon constituting interest expense and any shares issuable upon conversion of the security being accounted for in a manner similar to the treasury stock method. The effect of this method is that the shares potentially issuable upon conversion of the securities are not included in the calculation

of earnings per share until the conversion price is “in the money”, and the issuer is then assumed to issue the number of shares necessary to settle the conversion.

However, a proposal to change that accounting method has recently been made by the FASB. Under the proposal, cash settled convertible securities would be separated into their debt and equity components. The value assigned to the debt component would be the estimated fair value, as of the issuance date, of a similar debt instrument without the conversion feature, and the difference between the proceeds for the convertible debt and the amount reflected as a debt liability would be recorded as additional paid-in capital. As a result, the debt would be recorded at a discount reflecting its below market coupon interest rate. The debt would subsequently be accreted to its par value over its expected life, with the rate of interest that reflects the market rate at issuance being reflected on the income statement. This change in methodology would affect the calculations of net income and earnings per share for many issuers of cash settled convertible securities, including us.

Implementation of this proposal is ongoing and we cannot predict the exact methodology that will be imposed, which may differ materially from the foregoing description, or when any change will be finally implemented.

Joint venture investments could be adversely affected by our lack of sole decision-making authority, our reliance on co-venturers’ financial condition and disputes between us and our co-venturers.

We currently, and may in the future, co-invest with third parties through partnerships, joint ventures or other entities, acquiring non-controlling interests in or sharing responsibility for managing the affairs of a property,

partnership, joint venture or other entity. In that event, we would not be in a position to exercise sole decision-making authority regarding the property, partnership, joint venture or other entity. Investments in partnerships, joint ventures, or other entities may, under certain circumstances, involve risks not present when a third party is not involved, including the possibility that partners or co-venturers might become bankrupt or fail to fund their share of required capital contributions. Partners or co-venturers may have economic, tax or other business interests or goals which are inconsistent with our business interests or goals, and may be in a position to take actions contrary to our policies or objectives. Our joint venture partners may take actions that are not within our control, which would require us to dispose of the joint venture asset or transfer it to a taxable REIT subsidiary in order to maintain our status as a REIT. Such investments may also lead to impasses, for example, as to whether to sell a property, because neither we nor the partner or co-venturer would have full control over the partnership or joint venture. Disputes between us and partners or co-venturers may result in litigation or arbitration that would increase our expenses and prevent our officers and/or directors from focusing their time and effort on our day-to-day business. Consequently, actions by or disputes with partners or co-venturers may subject properties owned by the partnership or joint venture to additional risk. In addition, we may in certain circumstances be liable for the actions of our third-party partners or co-venturers. Finally, we may share information with our third-party partners or co-venturers. Finally, we may share information with our third-party partners or co-venturers that enables them to compete with us in the future. Each of these factors may result in returns on these investments being less than we expect or in losses and our financial and operating results may be adversely affected.

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

We depend on the efforts of key personnel, particularly Michael Foust, our Chief Executive Officer, A. William Stein, our Chief Financial Officer and Chief Investment Officer, Scott Peterson, our Senior Vice President, Acquisitions, and Christopher Crosby, our Senior Vice President, Sales and Technical Services, and James R. Trout, our Senior Vice President of Portfolio and Technical Operations.Services. They are important to our success for many reasons, including that each has a national or regional reputation in our industry and the investment community that attracts investors and business and investment opportunities and assists us in negotiations with investors, lenders, existing and potential tenants and industry personnel. If we lost their services, our business and investment opportunities and our relationships with lenders and other capital markets participants, existing and prospective tenants and industry personnel could suffer. Many of our other senior employees also have strong technology, finance and real estate

industry reputations. As a result, we have greater access to potential acquisitions, financing, leasing and other opportunities, and are better able to negotiate with tenants. As our number of competitors increases, it becomes more likely that a competitor would attempt to hire certain of these individuals away from us. The loss of any of these key personnel would result in the loss of these and other benefits and could materially and adversely affect our results of operations.

Ownership of properties located outside of the United States subjects us to foreign currency and related risks which may adversely impact our ability to make distributions.

We owned 14 properties located outside of the U.S. at December 31, 2008 and have a right of first offer with respect to another property. In addition, we are currently considering, and will in the future consider, additional international acquisitions.

The ownership of properties located outside of the U.S. subjects us to risk from fluctuations in exchange rates between foreign currencies and the U.S. dollar. We expect that our principal foreign currency exposure will be to the British pound and the Euro. Changes in the relation of these currencies to the U.S. dollar, including the recent increase of the U.S. dollar relative to the Euro and the British pound, will affect our revenues and operating margins, may materially adversely impact our financial condition, results of operations, cash flow, cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, the per share trading price of our common stock or preferred stock and our ability to satisfy our debt obligations.

We may attempt to mitigate some or all of the risk of currency fluctuation by financing our properties in the local currency denominations, although we cannot assure you that we will be able to do so or that this will be effective. We may also engage in direct hedging activities to mitigate the risks of exchange rate fluctuations.

Failure to hedge effectively against interest rate changes may adversely affect results of operations.

We seek to manage our exposure to interest rate volatility by using interest rate hedging arrangements, such as interest cap and interest rate swap agreements. These agreements involve risks, such as the risk that counterparties may fail to honor their obligations under these arrangements, that these arrangements may not be effective in reducing our exposure to interest rate changes and that a court could rule that such an agreement is not legally enforceable. Our policy is to use derivatives only to hedge interest rate risks related to our borrowings, not for speculative or trading purposes, and to enter into contracts only with major financial institutions based on their credit ratings and other factors. However, we may choose to change this policy in the future. Including loans currently subject to interest rate swaps, approximately 78%87% of our total indebtedness as of December 31, 20072008 was subject to fixed interest rates. We do not currently hedge our revolving credit facility and as our borrowings under our revolving credit facility increase, so will our percentage of indebtedness not subject to fixed rates and our exposure to interest rates increase. Hedging may reduce the overall returns on our investments. Failure to hedge effectively against interest rate changes may materially adversely affect our results of operations.

Our properties may not be suitable for lease to datacenter or traditional technology office tenants without significant expenditures or renovations.

Because many of our properties contain tenant improvements installed at our tenants’ expense, they may be better suited for a specific corporate enterprise datacenter user or technology industry tenant and could require modification in order for us to re-lease vacant space to another corporate enterprise datacenter user or technology industry tenant. The tenant improvements may also become outdated or obsolete as the result of technological change, the passage of time or other factors. In addition, our redevelopment space will generally require substantial improvement to be suitable for datacenter use. For the same reason, our properties also may not be suitable for lease to traditional office tenants without significant expenditures or renovations. As a result, we may be required to invest significant amounts or offer significant discounts to tenants in order to lease or re-lease that space, either of which could adversely affect our financial and operating results.

Ownership of properties located outside of the United States subjects us to foreign currency and related risks which may adversely impact our ability to make distributions.

We owned 13 properties located outside of the U.S. at December 31, 2007 and have a right of first offer with respect to another property. In addition, we are currently considering, and will in the future consider, additional international acquisitions.

The ownership of properties located outside of the U.S. subjects us to risk from fluctuations in exchange rates between foreign currencies and the U.S. dollar. We expect that our principal foreign currency exposure will be to the British pound and the Euro. Changes in the relation of these currencies to U.S. dollars will affect our revenues and operating margins, may materially adversely impact our financial condition, results of operations, cash flow, cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, the per share trading price of our common stock or preferred stock, our ability to satisfy our debt obligations and our ability to qualify as a REIT.

We may attempt to mitigate some or all of the risk of currency fluctuation by financing our properties in the local currency denominations, although we cannot assure you that we will be able to do so or that this will be effective. We may also engage in direct hedging activities to mitigate the risks of exchange rate fluctuations.

Any income recognized with respect to foreign currency exchange rate hedging activities may not qualify under the 75% gross income test or the 95% gross income test that we must satisfy annually in order to qualify and maintain our status as a REIT.

Acquisition, development, redevelopment, operation and ownership of foreign properties involve risks greater than those faced by us in the U.S.

Foreign real estate investments usually involve risks not generally associated with investments in the United States. Our international acquisitions, developments, redevelopments, operations are subject to a number of risks, including:

Our inability to overcome these risks could adversely affect our foreign operations and could harm our business and results of operations.

Risks Related to the Real Estate Industry

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

Our ability to pay cash dividends to our stockholders and our operating partnership’s ability to pay distributions to its unitholders, depends on our ability to generate revenues in excess of expenses, scheduled principal payments on debt and capital expenditure requirements. Events and conditions generally applicable to owners and operators of real property that are beyond our control may decrease cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, and the value of our properties. These events and conditions include:

In addition, periods of economic slowdown or recession, rising interest rates or credit spreads, limited or no access to debt or equity capital or declining demand for real estate, or the public perception that any of these events may occur, could result in a general decline in rents or an increased incidence of defaults under existing leases, which would materially adversely affect our financial condition, results of operations, cash flow, cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, per share trading price of our common stock or preferred stock and ability to satisfy our debt service obligations.

Illiquidity of real estate investments could significantly impede our ability to respond to adverse changes in the performance of our properties and harm our financial condition.

Because real estate investments are relatively illiquid and because there may be even fewer buyers for our specialized real estate, our ability to promptly sell properties in our portfolio in response to adverse changes in their performance may be limited, which may harm our financial condition. The real estate market is affected by many factors that are beyond our control, including:

We could incur significant costs related to government regulation and private litigation over environmental matters.

Under various laws relating to the protection of the environment, a current or previous owner or operator of real estate may be liable for contamination resulting from the presence or discharge of hazardous or toxic substances at that property, and may be required to investigate and clean up such contamination at or emanating from that property. Such laws often impose liability without regard to whether the owner or operator knew of, or was responsible for, the presence of the contaminants, and the liability may be joint and several. Previous owners used some of our properties for industrial and retail purposes, so those properties may contain some level of environmental contamination. The presence of contamination or the failure to remediate contamination at our properties may expose us to third-party liability or materially adversely affect our ability to sell, lease or develop the real estate or to borrow using the real estate as collateral.

Some of the properties may contain asbestos-containing building materials. Environmental laws require that asbestos-containing building materials be properly managed and maintained, and may impose fines and penalties on building owners or operators for failure to comply with these requirements. These laws may also allow third parties to seek recovery from owners or operators for personal injury associated with exposure to asbestos-containing building materials.

In addition, some of our tenants, particularly those in the biotechnology and life sciences industry and those in the technology manufacturing industry, routinely handle hazardous substances and wastes as part of their operations at our properties. Environmental laws and regulations subject our tenants, and potentially us, to liability resulting from these activities or from previous industrial or retail uses of those properties. Environmental liabilities could also affect a tenant’s ability to make rental payments to us.

Existing conditions at some of our properties may expose us to liability related to environmental matters.

Independent environmental consultants have conducted Phase I or similar environmental site assessments on all of the properties in our portfolio. Site assessments are intended to discover and evaluate information regarding the environmental condition of the surveyed property and surrounding properties. These assessments do not generally include soil samplings, subsurface investigations or an asbestos survey and the assessments may fail to reveal all environmental conditions, liabilities or compliance concerns. In addition material environmental conditions, liabilities or compliance concerns may arise after these reviews are completed or may arise in the future. Future laws, ordinances or regulations may impose additional material environmental liability.

We cannot assure you that costs of future environmental compliance will not affect our ability to pay cash dividends to our stockholders or our operating partnership’s ability to pay distributions to its unitholders or that such costs or other remedial measures will not have a material adverse effect on our business, assets or results of operations.

Our properties may contain or develop harmful mold or suffer from other air quality issues, which could lead to liability for adverse health effects and costs to remedy the problem.

When excessive moisture accumulates in buildings or on building materials, mold may grow, particularly if the moisture problem remains undiscovered or is not addressed over a period of time. Some molds may produce airborne toxins or irritants. Indoor air quality issues can also stem from inadequate ventilation, chemical contamination from indoor or outdoor sources and other biological contaminants such as pollen, viruses and bacteria. Indoor exposure to airborne toxins or irritants above certain levels can be alleged to cause a variety of adverse health effects and symptoms, including allergic or other reactions. As a result, the presence of significant mold or other airborne contaminants at any of our properties could require us to undertake a costly remediation program to contain or remove the mold or other airborne contaminants from the affected property or increase indoor ventilation. In addition, the presence of significant mold or other airborne contaminants could expose us to liability from our tenants, employees of our tenants and others if property damage or health concerns arise.

We may incur significant costs complying with the Americans with Disabilities Act and similar laws.

Under the Americans with Disabilities Act of 1990, or the ADA, all public accommodations must meet federal requirements related to access and use by disabled persons. We have not conducted an audit or investigation of all of our properties to determine our compliance with the ADA. If one or more of the properties in our portfolio does not comply with the ADA, then we would be required to incur additional costs to bring the property into compliance. Additional federal, state and local laws also may require modifications to our properties, or restrict our ability to renovate our properties. We cannot predict the ultimate cost of compliance with the ADA or other legislation. If we incur substantial costs to comply with the ADA and any other similar legislation, our financial condition, results of operations, cash flow, cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, per share trading price of our common stock or preferred stock and our ability to satisfy our debt service obligations could be materially adversely affected.

We may incur significant costs complying with other regulations.

The properties in our portfolio are subject to various federal, state and local regulations, such as state and local fire and life safety regulations. If we fail to comply with these various regulations, we may have to pay

fines or private damage awards. In addition, we do not know whether existing regulations will change or whether future regulations will require us to make significant unanticipated expenditures that will materially adversely impact our financial condition, results of operations, cash flow, cash available for distribution, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, per share trading price of our common stock or preferred stock and our ability to satisfy our debt service obligations.

Risks Related to Our Organizational Structure

Conflicts of interest may exist or could arise in the future with holders of units in our operating partnership.

Conflicts of interest may exist or could arise in the future as a result of the relationships between us and our affiliates, on the one hand, and our operating partnership or any partner thereof, on the other. Our directors and officers have duties to our company and our stockholders under Maryland law in connection with their management of our company. At the same time, we, as general partner, have fiduciary duties under Maryland law to our operating partnership and to the limited partners in connection with the management of our operating partnership. Our duties as general partner to our operating partnership and its partners may come into conflict with the duties of our directors and officers to our company and our stockholders. Under Maryland law, a general partner of a Maryland limited partnership owes its limited partners the duties of good faith, fairness and loyalty, unless the partnership agreement provides otherwise. The partnership agreement of our operating partnership

provides that for so long as we own a controlling interest in our operating partnership, any conflict that cannot be resolved in a manner not adverse to either our stockholders or the limited partners will be resolved in favor of our stockholders.

The provisions of Maryland law that allow the fiduciary duties of a general partner to be modified by a partnership agreement have not been tested in a court of law, and we have not obtained an opinion of counsel covering the provisions set forth in the partnership agreement that purport to waive or restrict our fiduciary duties.

We are also subject to the following additional conflicts of interest with holders of units in our operating partnership:

We may pursue less vigorous enforcement of terms of certain agreements because of conflicts of interest with GI Partners.GI Partners and its related fund, own a property on which we have a right of first offer. GI Partners Fund II, LLP, or GI Partners II, owns The tel(x) Group, an operator of “Meet-Me-Room” network interconnection facilities that leases 87,305101,581 square feet from us under ten20 lease agreements. Richard Magnuson, the Chairman of our board of directors, is and will continue to be, the chief executive officer of the advisor to GI Partners and GI Partners II. In the future, we may enter into additional agreements with The tel(x) Group or other companies owned by GI Partners or GI Partners II or other GI Partners funds. We may choose not to enforce, or to enforce less vigorously, our rights under theses agreements because of our desire to maintain our ongoing relationship with GI Partners and Mr. Magnuson.

Tax consequences upon sale or refinancing.Sales of properties and repayment of certain indebtedness will affect holders of common units in our operating partnership and our stockholders differently. The parties who contributed the 200 Paul Avenue 1-4 and 1100 Space Park Drive properties to our operating partnership would incur adverse tax consequences upon the sale of these properties and on the repayment of related debt which differ from the tax consequences to us and our stockholders. Consequently, these holders of common units in our operating 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 our operating partnership to determine when to refinance or repay debt or whether, when, and on what terms to sell a property, any such decision would require the approval of our board of directors. Certain of our directors and executive officers 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.

Our charter and Maryland law contain provisions that may delay, defer or prevent a change of control transaction.

Our charter and the articles supplementary with respect to the preferred stock contain 9.8% ownership limits.Our charter, subject to certain exceptions, authorizes our directors to take such actions as are necessary and desirable to preserve our qualification as a REIT and to limit any person to actual or constructive ownership of no more than 9.8% (by value or by number of shares, whichever is more restrictive) of the outstanding shares of our common stock, 9.8% (by value or by number of shares, whichever is more restrictive) of the outstanding shares of any series of preferred stock and 9.8% of the value of our outstanding capital stock. Our board of directors, in its sole discretion, may exempt (prospectively or retroactively) a proposed transferee from the ownership limit. However, our board of directors may not grant an exemption from the ownership limit to any proposed transferee whose direct or indirect ownership of more than 9.8% of the outstanding shares of our common stock, more than 9.8% of the outstanding shares of any series of preferred stock or more than 9.8% of the value of our outstanding capital stock could jeopardize our status as a REIT. These restrictions on transferability and ownership will not apply if our board of directors determines that it is no longer in our best interests to attempt to qualify, or to continue to qualify, as a REIT. The ownership limit may delay, defer or prevent a transaction or a change of control that might be in the best interest of our common or preferred stockholders.

We could increase the number of authorized shares of stock and issue stock without stockholder approval.Our charter authorizes our board of directors, without stockholder approval, to amend the charter to increase the aggregate number of authorized shares of stock or the number of authorized shares of stock of any class or series that we have authority to issue, to issue authorized but unissued shares of our common stock or preferred stock and, subject to the voting rights of holders of preferred stock, to classify or reclassify any unissued shares of our common stock or preferred stock and to set the preferences, rights and other terms of such classified or reclassified shares. Although our board of directors has no such intention at the present time, it could establish a series of preferred stock that could, depending on the terms of such series, delay, defer or prevent a transaction or a change of control that might be in the best interest of our common or preferred stockholders.

Certain provisions of Maryland law could inhibit changes in control. Certain provisions of the Maryland General Corporation Law, or MGCL, may have the effect of impeding a third party from making a proposal to acquire us or of impeding a change of control under circumstances that otherwise could be in the best interests of our common or preferred stockholders, including:

We have opted out of these provisions of the MGCL, in the case of the business combination provisions of the MGCL by resolution of our board of directors, and in the case of the control share provisions of the MGCL pursuant to a provision in our bylaws. However, our board of directors may by resolution elect to opt in to the

business combination provisions of the MGCL and we may, by amendment to our bylaws, opt in to the control share provisions of the MGCL in the future.

The provisions of our charter on removal of directors and the advance notice provisions of the bylaws could delay, defer or prevent a transaction or a change of control of our company that might be in the best interest of our common or preferred stockholders. Likewise, if our company’s board of directors were to opt in to the business combination provisions of the MGCL or the provisions of Title 3, Subtitle 8 of the MGCL not currently applicable to us, or if the provision in our bylaws opting out of the control share acquisition provisions of the MGCL were rescinded, these provisions of the MGCL could have similar anti-takeover effects. Further, our partnership agreement provides that our company may not engage in any merger, consolidation or other combination with or into another person, sale of all or substantially all of our assets or any reclassification or any recapitalization or change in outstanding shares of our common stock, unless in connection with such transaction we obtain the consent of the holders of at least 35% of our operating partnership’s common and long-term incentive units (including units held by us), and certain other conditions are met.

Our board of directors may change our investment and financing policies without stockholder approval and we may become more highly leveraged, which may increase our risk of default under our debt obligations.

Our board of directors adopted a policy of limiting our indebtedness to 60% of our total market capitalization. Our total market capitalization is defined as the sum of the market value of our outstanding common stock (which may decrease, thereby increasing our debt to total capitalization ratio), excluding options issued under our incentive award plan, plus the aggregate value of the units not held by us, plus the liquidation preference of outstanding preferred stock, plus the book value of our total consolidated indebtedness. However, our organizational documents do not limit the amount or percentage of indebtedness, funded or otherwise, that we may incur. Our board of directors may alter or eliminate our current policy on borrowing at any time without stockholder approval. If this policy changed, we could become more highly leveraged which could result in an increase in our debt service and which could materially adversely affect our cash flow and our ability to make distributions, including cash available for us to pay dividends to our stockholders or for our operating partnership to pay distributions to its unitholders, including us. Higher leverage also increases the risk of default on our obligations.

Our rights and the rights of our stockholders to take action against our directors and officers are limited.

Maryland law provides that our directors and officers have no liability in their capacities as directors or officers if they perform their duties in good faith, in a manner they reasonably believe to be in our best interests and with the care that an ordinarily prudent person in a like position would use under similar circumstances. As permitted by the MGCL, our charter limits the liability of our directors and officers to us and our stockholders for money damages, except for liability resulting from:

In addition, our charter authorizes us to obligate our company, and our bylaws require us, to indemnify our directors and officers for actions taken by them in those capacities and to pay or reimburse their reasonable expenses in advance of final disposition of a proceeding to the maximum extent permitted by Maryland law and we have entered in indemnification agreements with our officers and directors. As a result, we and our stockholders may have more limited rights against our directors and officers than might otherwise exist under common law. Accordingly, in the event that actions taken in good faith by any of our directors or officers impede the performance of our company, your ability to recover damages from that director or officer will be limited.

Risks Related to Our Status as a REIT

Failure to qualify as a REIT would have significant adverse consequences to us and the value of our stock.

We have operated and intend to continue operating in a manner that we believe will allow us to qualify as a REIT for federal income tax purposes under the Code. We have not requested and do not plan to request a ruling from the IRS that we qualify as a REIT. If we lose our REIT status, we will face serious tax consequences that would substantially reduce our cash available for distribution, including cash available to pay dividends to our preferred stockholders or make distributions to our common stockholders, for each of the years involved because:

In addition, if we fail to qualify as a REIT, we will not be required to make distributions to stockholders. As a result of all these factors, our failure to qualify as a REIT also could impair our ability to expand our business and raise capital, and would materially adversely affect the value of our capital stock.

Qualification as a REIT involves the application of highly technical and complex Code provisions for which there are only limited judicial and administrative interpretations. The complexity of these provisions and of the applicable Treasury Regulations that have been promulgated under the Code is greater in the case of a REIT that, like us, holds its assets through a partnership. Our ability to qualify as a REIT may be affected by facts and circumstances that are not entirely within our control. In order to qualify as a REIT, we must satisfy a number of requirements, including requirements regarding the composition of our assets and a requirement that at least 95% of our gross income in any year must be derived from qualifying sources, such as “rents from real property.” Also, we must make distributions to stockholders aggregating annually at least 90% of our net taxable income, excluding net capital gains. In addition, legislation, new regulations, administrative interpretations or court decisions may materially adversely affect our investors, our ability to qualify as a REIT for federal income tax purposes or the desirability of an investment in a REIT relative to other investments.

Even if we qualify as a REIT for federal income tax purposes, we may be subject to some federal, state and local taxes on our income or property and, in certain cases, a 100% penalty tax, in the event we sell property as a dealer. In addition, our domestic taxable REIT subsidiary could be subject to Federal and state taxes, and our foreign properties and companies are subject to tax in the jurisdictions in which they operate and are located.

To maintain our REIT status, we may be forced to borrow funds on a short-term basis during unfavorable market conditions.

To qualify as a REIT, we generally must distribute to our stockholders at least 90% of our net taxable income each year, excluding capital gains, and we will be subject to regular corporate income taxes to the extent that we distribute less than 100% of our net taxable income each year. In addition, we will be subject to a 4% nondeductible excise tax on the amount, if any, by which distributions 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. In orderWhile historically we have satisfied these distribution requirements by making cash distributions to maintain our shareholders, a REIT status and avoidis permitted to satisfy these requirements by making distributions of cash or other property, including, in limited circumstances, its own stock. For distributions with respect to taxable years ending on or before December 31, 2009, recent Internal Revenue Service guidance allows us to satisfy up to 90% of the paymentdistribution requirements discussed above through the distribution of income and excise taxes,shares of our stock, if certain conditions are met. Assuming we continue to satisfy these distributions requirements with cash, 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. These short-term borrowing needs could result from differences in timing between the actual receipt of cash and inclusion 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 power of our board of directors to revoke our REIT election without stockholder approval may cause adverse consequences to our stockholders.

Our charter provides that our board of directors may revoke or otherwise terminate our REIT election, without the approval of our stockholders, if it determines that it is no longer in our best interests to continue to qualify as a REIT. If we cease to qualify as a REIT, we would become subject to U.S. federal income tax on our taxable income and we would no longer be required to distribute most of our taxable income to our stockholders, which may have adverse consequences on the total return to our common or preferred stockholders.

Forward-Looking Statements

We make statements in this report that are forward-looking statements within the meaning of the federal securities laws. In particular, statements pertaining to our capital resources, portfolio performance and results of operations contain forward-looking statements. Likewise, all of our statements regarding anticipated market conditions, demographics and results of operations are forward-looking statements. You can identify forward-looking statements by the use of forward-looking terminology such as “believes,” “expects,” “may,” “will,” “should,” “seeks,” “approximately,” “intends,” “plans,” “pro forma,” “estimates” or “anticipates” or the negative of these words and phrases or similar words or phrases which are predictions of or indicate future events or trends and which do not relate solely to historical matters. You can also identify forward looking statements by discussions of strategy, plans or intentions.

Forward-looking statements involve numerous risks and uncertainties and you should not rely on them as predictions of future events. Forward-looking statements depend on assumptions, data or methods which may be incorrect or imprecise and we may not be able to realize them. We do not guarantee that the transactions and events described will happen as described (or that they will happen at all). The following factors, among others, could cause actual results and future events to differ materially from those set forth or contemplated in the forward-looking statements:

While forward-looking statements reflect our good faith beliefs, they are not guaranties of future performance. We disclaim any obligation to publicly update or revise any forward-looking statement to reflect changes in underlying assumptions or factors, new information, data or methods, future events or other changes. For a further discussion of these and other factors that could impact our future results, performance or transactions, see the sections above.

None.Not applicable.

Our Portfolio

As of December 31, 2007,2008, we owned 7075 properties through our operating partnership, excluding one property held as an investment in an unconsolidated joint venture. These properties are primarily located throughout North America, with 1213 properties located in Europe, and contain a total of approximately 12.313.0 million net rentable square feet including 1.81.6 million square feet held for redevelopment. The following table presents an overview of our portfolio of properties excluding the one property held as an investment in a joint venture, based on information as of December 31, 2007.2008. All properties are held in fee except as otherwise indicated. Please refer to note 6 in the notes to the consolidated financial statements included in Part II, Item 8 of this Annual Report on Form 10-K for a description of all applicable encumbrances as of December 31, 2008.

Tenant Diversification

As of December 31, 20072008 our portfolio was leased to 414approximately 350 companies, many of which are nationally recognized firms. The following table sets forth information regarding the 1520 largest tenants in our portfolio based on annualized rent as of December 31, 2007.2008.

Lease Distribution

The following table sets forth information relating to the distribution of leases in the properties in our portfolio, based on net rentable square feet (excluding space held for redevelopment) under lease as of December 31, 2007.2008.

(2)	Annualized rent represents the monthly contractual rent under existing leases as of December 31, 2008 multiplied by 12.

Lease Expirations

The following table sets forth a summary schedule of the lease expirations for leases in place as of December 31, 20072008 plus available space for each of the next ten full calendar years at the properties in our portfolio. Unless otherwise stated in the footnotes, the information set forth in the table assumes that tenants exercise no renewal options and all early termination rights.