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

FORM 10-K

FOR ANNUAL AND TRANSITION REPORTS PURSUANT TO SECTIONS 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

(Mark one)

ý         ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2004

or

o         TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from            to          

Commission file number 1-14023

Corporate Office Properties Trust

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code:  (410) 730-9092

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.  ýYes   o 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.  o

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

The aggregate market value of the voting and nonvoting common equity held by non-affiliates of the registrant was approximately
$819.0 million, as calculated using the closing price of the common shares of beneficial interest on the New York Stock Exchange and our outstanding shares as of June 30, 2004; for purposes of calculating this amount only, affiliates are defined as Trustees, executive owners and beneficial owners of more than 10% of the Registrant’s outstanding common shares of beneficial interest.  At February 28, 2005, 36,851,823 shares of the Registrant’s common shares of beneficial interest, $0.01 par value, were outstanding.

Portions of the annual shareholder report for the year ended December 31, 2004 are incorporated by reference into Parts I and II of this report and portions of the proxy statement of the Registrant for its 2005 Annual Meeting of Shareholders to be filed within 120 days after the end of the fiscal year covered by this Form 10-K are incorporated by reference into Part III of this Form 10-K.

PART I

Item 1. Business

OUR COMPANY

General.  We are a fully-integrated and self-managed real estate investment trust (“REIT”) that focuses on the ownership, management, leasing, acquisition and development of suburban office properties.  We typically focus our operations geographically in select submarkets that are attractive to our tenant base and in which we believe we can establish a critical mass of square footage.  At December 31, 2004, all of our properties were located in the Mid-Atlantic region of the United States, although in accordance with our strategy of focusing on submarkets that are attractive to our tenants, we may seek to expand our operations outside of that region.  As of December 31, 2004, we owned:

•                  145 operating office properties in Maryland, Pennsylvania, New Jersey and Virginia containing 12.0 million rentable square feet that were 94.0% occupied (including two properties totaling 213,261 square feet owned through joint ventures);

•                  11 office properties under construction or development that we estimate will total approximately 1.4 million square feet upon completion (including one property that we estimate will total approximately 82,000 square feet owned through a joint venture) and

•                  land parcels totaling 218 acres that were contiguous to certain of our operating properties and potentially developable into approximately 3.6 million square feet (including (1) six acres potentially developable into approximately 68,400 square feet that we owned through joint ventures and (2) 33 acres potentially developable into approximately 422,000 square feet that we did not own as of December 31, 2004 but, rather, held options to acquire).

We conduct almost all of our operations through our operating partnership, Corporate Office Properties, L.P. (the “Operating Partnership”), a Delaware limited partnership, of which we are the sole general partner.  The Operating Partnership owns real estate both directly and through subsidiaries.  The Operating Partnership also owns Corporate Office Management, Inc. (“COMI”) (together with its subsidiaries defined as the “Service Companies”).  COMI owns 100% of three subsidiaries: Corporate Realty Management, LLC (“CRM”), Corporate Development Services, LLC (“CDS”) and Corporate Cooling and Controls, LLC (“CC&C”).  CRM manages most of our properties and also provides corporate facilities management for select third parties.  CDS provides construction and development services predominantly to us.  CC&C provides heating and air conditioning installation, maintenance, repair and controls services.

Interests in our Operating Partnership are in the form of preferred and common units.  As of December 31, 2004, we owned approximately 95% of the outstanding preferred units and approximately 80% of the outstanding common units.  The remaining preferred and common units in our Operating Partnership were owned by third parties, which included certain of our officers and Trustees.

We believe that we are organized and have operated in a manner that permits us to satisfy the requirements for taxation as a REIT under the Internal Revenue Code of 1986, as amended, and we intend to continue to operate in such a manner.  If we qualify for taxation as a REIT, we generally will not be subject to Federal income tax on our taxable income that is distributed to our shareholders.  A REIT is subject to a number of organizational and operational requirements, including a requirement that it distribute to its shareholders at least 90% of its annual REIT taxable income (excluding net capital gains).

Our executive offices are located at 8815 Centre Park Drive, Suite 400, Columbia, Maryland 21045 and our telephone number is (410) 730-9092.

Corporate Office Properties Trust’s Internet address is www.copt.com.  We make available on our Internet site free of charge our annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act as soon as reasonably possible after we file such material with the Securities and Exchange Commission.  In addition, we have made available on our website under the heading “Corporate Governance” the charters for our Board of Trustees’ Audit Committee, Nominating and Corporate Governance Committee and Compensation Committee, as well as our Corporate Governance Guidelines, Code of Business Conduct and Ethics and Code of Ethics for Financial Officers.  We intend to make available on our website any future amendments or waivers to our Code of Business Conduct and Ethics and Code of Ethics for Financial Officers within four business days after any such amendments or waivers.  The information on our Internet site is not part of this report.

4

Significant 2004 Developments

During 2004, we:

•                  acquired 22 office properties totaling 1.6 million square feet for $261.4 million and seven parcels of land for $22.9 million. Of the buildings acquired, three were located in Northern Virginia, 17 in St Mary’s and King George Counties (located in Maryland and Virginia, respectively), one in the Suburban Maryland region and one in Northern Baltimore County.  These acquisitions were financed using the following: (1) $160.3 million from borrowings of new and assumed mortgage loans; (2) $104.3 million in borrowings from our Revolving Credit Facility; (3) $8.8 million from preferred units in the Operating Partnership issued; (4) $4.0 million from common share sale proceeds; and (5) cash reserves for the balance;

•                  acquired our joint venture partner’s interest in a consolidated joint venture for $4.9 million.  Through this acquisition, we acquired an office property totaling 156,730 square feet and assumed an $11.8 million mortgage loan that was subsequently refinanced;

•                  fully placed into service three newly-constructed buildings totaling 300,691 square feet;

•                  had construction underway on five new buildings and pre-construction activities underway on four new buildings;

•                  raised $115.4 million from the underwritten public offering of common shares of beneficial interest (“common shares”), of which $31.3 million was used to fund the redemption of our Series B Preferred Shares of beneficial interest, $26.0 million was used to prepay a mortgage loan and the balance was used to pay down our primary revolving credit facility (the “Revolving Credit Facility”).  These public offerings included the following:

•                  2,750,000 common shares at a price of $21.243 per share; and

•                  2,283,600 common shares at a price of $25.10 per share;

•                  obtained a new Revolving Credit Facility with a number of lenders led by Wachovia Bank, National Association.  The facility has a maximum principal balance of $300.0 million, a three year term (with an additional one-year extension available) and a variable interest rate based on the 30-day LIBOR rate plus 1.25% to 1.55% (as determined by our leverage levels at different points in time);

•                  obtained $307.7 million in borrowings from new and assumed mortgage and other loans, excluding our Revolving Credit Facility.  We used these borrowings for the following: (1) $160.3 million to finance acquisitions; (2) $64.0 million to pay down our Revolving Credit Facility; (3) $43.5 million to refinance existing debt; (4) $28.9 million to finance construction activities; and (5) the balance to fund cash reserves; and

•                  converted, upon the election of the holder of our Series D Preferred Shares of beneficial interest, such preferred shares into 1,196,800 common shares.

Subsequent Events

Subsequent to January 1, 2005, the following events took place:

•                  On January 28, 2005, we acquired a 19-acre land parcel located in Chantilly, Virginia for a purchase price of $7.1 million.  This acquisition was financed using borrowings under our Revolving Credit Facility; and

•                  On February 24, 2005, the following events took place:

•                  Clay W. Hamlin, III, our Chief Executive Officer, retired effective April 1, 2005.  Mr. Hamlin will remain on the Board of Trustees, of which he was appointed Vice Chairman effective April 1, 2005.  He will also enter into a three-year consulting agreement with us effective April 1, 2005 to assist with acquisitions and strategic initiatives;

•                  Randall M. Griffin, our current President and Chief Operating Officer, was appointed to the position of President and Chief Executive Officer effective April 1, 2005.  Mr. Griffin was also elected as a Class I Trustee of our Board of Trustees effective February 24, 2005.  The terms of our Class I Trustees will expire upon the election of their successors at our next annual shareholder meeting, to be held on May 19, 2005 (the “2005 Annual Meeting”).  Mr. Griffin was nominated to stand for re-election at that time; and

•                  Betsy Z. Cohen, a current member of our Board of Trustees, informed us that she will not stand for re-election at the 2005 Annual Meeting.

5

Corporate Objectives and Strategies

Our primary objectives are to achieve sustainable long-term growth in results of operations and to maximize long-term shareholder value.  We seek to achieve these objectives through focusing on the ownership, management, leasing, acquisition and development of suburban office properties.  Important elements of our strategy are set forth below:

Geographic Focus.  We focus our operations in select submarkets where we believe that we already possess or can achieve the critical mass necessary to maximize management efficiencies, operating synergies and competitive advantages through our acquisition, property management and development programs.  The attributes we look for in selecting submarkets include, among others; (1) proximity to large demand drivers; (2) strong demographics; (3) attractiveness to high quality tenants, including our existing tenants; (4) potential for growth and stability in economic down cycles and (5) future acquisition and development opportunities.  When we select a submarket, our strategy generally involves establishing an initial presence by acquiring properties in that submarket and then increasing our ownership through future acquisitions and development until we own a significant portion of the rental space of the same class as our properties in that submarket.  We may pursue selective expansion opportunities outside the Mid-Atlantic region of the United States, typically to meet the anticipated needs of our existing and future tenants.

Office Park Focus.  We focus on owning and operating properties located in established suburban corporate office parks.  We believe the suburban office park environment generally attracts longer-term tenants, including high-quality corporations seeking to attract and retain quality work forces, because these parks are typically situated along major transportation routes with easy access to support services, amenities and residential communities.

High Quality Tenant Focus.  We focus on tenants that are large, financially sound entities with significant long-term space requirements.  To enhance the stability of our cash flow, we typically structure our leases with terms ranging from three to ten years.  We believe that this strategy enables us to establish long-term relationships with quality tenants and, coupled with our geographic and submarket focus, enhances our ability to become the landlord of choice in our targeted markets.  Given the terms of our leases, we monitor the timing of our lease maturities with the goal being that such timing should not be highly concentrated in a given one-year or five-year period.

 Intelligence and Defense Industry Focus.  A high concentration of our revenues is generated from tenants in the United States intelligence and defense industry (comprised of the United States Government and intelligence and defense contractors).  This industry is particularly interested in the submarkets where our properties are located and the types of properties and service that we are able to provide.  We also believe that our experience and existing relationships in the industry position us well to continue and grow on this focus.  We seek to reinforce and expand our relationships with current and prospective tenants in the intelligence and defense industry, while monitoring our levels of concentration from a business risk perspective.

Acquisition Strategies.  We generally pursue the acquisition of suburban office properties through a three-part acquisition strategy; this strategy includes targeting: (1) entity acquisitions of significant portfolios along with their management to establish prominent ownership positions in new neighboring regions and enhance our management infrastructure; (2) portfolio purchases to enhance our existing submarket positions as well as enter selective new neighboring regions; and (3) opportunistic acquisitions of individual properties in our existing regions.  We typically seek to make acquisitions at attractive yields and below replacement cost.  We also typically seek to increase cash flow and enhance the underlying value of each acquisition through repositioning the properties and capitalizing on existing below market leases and expansion opportunities.

Property Development Strategies.  We balance our acquisition program through selective development and expansion of suburban office properties as market conditions and leasing opportunities support favorable risk-adjusted returns.  We pursue development opportunities principally in response to the needs of existing and prospective new tenants. We generally develop sites that are in proximity to our existing properties.  We believe that developing such sites enhances our ability to effectively meet tenant needs and efficiently provide critical tenant services.

Tenant Services.  We seek to capitalize on our geographic focus and critical mass of properties in our core regions by providing high level, comprehensive services to our tenants.  We conduct most of our tenant services activities through our subsidiary service companies.  We believe that providing such services is an integral part of our ability to achieve consistently high levels of tenant satisfaction and retention.

6

Internal Growth Strategies.  We aggressively manage our portfolio to maximize the operating performance of each property through: (1) proactive property management and leasing; (2) achieving operating efficiencies through increasing economies of scale and, where possible, aggregating vendor contracts to achieve volume pricing discounts; (3) renewing tenant leases and re-tenanting at increased rents where market conditions permit; and (4) expanding our tenant and real estate service capabilities.  These strategies are designed to promote tenant satisfaction, resulting in higher tenant retention and the attraction of new tenants.

Financing Policy

We pursue a capitalization strategy aimed at maintaining a flexible capital structure in order to facilitate consistent growth and performance in the face of differing market conditions.  Key components of our policy are set forth below:

Debt Strategy.  We primarily utilize property-level mortgage debt as opposed to corporate unsecured debt.  We believe that the commercial mortgage debt market is generally a more stable market, providing us with greater access to capital on a more consistent basis and, generally, on more favorable terms.  Additionally, we seek to utilize long-term, fixed-rate debt, which we believe enhances the stability of our cash flow.  One aspect of how we manage our financing policy involves monitoring the relationship of certain measures of earnings to certain financing cost requirements; these relationships are known as coverage ratios.  One coverage ratio on which our financing policy focuses is fixed charge coverage ratio (defined as various measures of results of operations divided by the sum of (1) interest expense on continuing and discontinued operations; (2) dividends on preferred shares and (3) distributions on preferred units in our Operating Partnership not owned by us).  Coverage ratios such as fixed charge coverage ratio are important to us in evaluating whether our operations are sufficient to satisfy the cash flow requirements of our loans and equity holders, including minority interest holders.  Another aspect to our financing policy involves monitoring the relationship of our total variable-rate debt to both our total assets and total debt; this is important to us in limiting the amount of our debt that is subject to future increases in interest rates.  We also closely monitor the timing of our debt maturities to ensure that the maximum maturities of debt in any year, both including and excluding our primary revolving credit facility, do not exceed a defined percentage of total assets.

Equity Strategy.  When conditions warrant, we issue common and preferred equity.  We also seek to maximize the benefits of our Operating Partnership’s organizational structure by utilizing, where appropriate, the issuance of units in our Operating Partnership as an equity source to finance our property acquisition program.  This strategy provides prospective property sellers the ability to defer taxable gains by receiving our units in lieu of cash and reduces the need for us to access the equity and debt markets.

Mortgage Loans Payable

For information relating to future maturities of our mortgage loans payable, you should refer to the section entitled “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and Note 9 to our Consolidated Financial Statements, both of which are included in Exhibit 13.1 to this Form 10-K and are incorporated herein by reference.

Industry Segments

We operate in one industry segment: suburban office real estate.  At December 31, 2004, our suburban office real estate operations had seven primary geographical segments all located in the Mid-Atlantic region of the United States: (1) the Baltimore/Washington Corridor (defined as the Maryland counties of Howard and Anne Arundel); (2) Northern Virginia (defined as Fairfax County, Virginia); (3) Northern Central New Jersey; (4) St. Mary’s & King George Counties (located in Maryland and Virginia, respectively); (5) Greater Philadelphia, Pennsylvania; (6) Greater Harrisburg, Pennsylvania and (7) Suburban Maryland (defined as the Maryland counties of Montgomery and Prince George’s).  For information relating to these geographic segments, you should refer to Note 16 to our Consolidated Financial Statements, which are included in Exhibit 13.1 to this Form 10-K and are incorporated herein by reference.

Employees

We employed 225 persons as of December 31, 2004.  We believe that our relations with our employees are good.

Competition

The commercial real estate market is highly competitive.  Numerous commercial properties compete for tenants with our properties.  Some of the properties competing with ours may be newer or have more desirable locations or the competing

7

RISK FACTORS

Set forth below are risks and uncertainties relating to our business and the ownership of our securities.  You should carefully consider each of the risks and uncertainties below and all of the information in this Form 10-K and its Exhibits, including Exhibit 13.1, which sets forth portions of the Annual Report to Shareholders of Corporate Office Properties Trust for the year ended December 31, 2004.

We may suffer adverse consequences as a result of our reliance on rental revenues for our income.  We earn revenue from renting our properties.  Our operating costs do not necessarily fluctuate in relation to changes in our rental revenue.  This means that our costs will not necessarily decline and may increase even if our revenues decline.

For new tenants or upon lease expiration for existing tenants, we generally must make improvements and pay other tenant-related costs for which we may not receive increased rents.  We also make building-related capital improvements for which tenants may not reimburse us.

If our properties do not generate revenue sufficient to meet our operating expenses and capital costs, we may have to borrow additional amounts to cover these costs.  In such circumstances, we would likely have lower profits or possibly incur losses.  We may also find in such circumstances that we are unable to borrow to cover such costs, in which case our operations could be adversely affected.  Moreover, there may be less or no cash available for distributions to our shareholders.

Adverse developments concerning some of our key tenants could have a negative impact on our revenue.  As of December 31, 2004, 20 tenants accounted for 59.4% of our portfolio annualized rental revenue, and five of these tenants accounted for 31.7% of our portfolio annualized rental revenue. We computed the annualized rental revenue by multiplying by 12 the sum of monthly contractual base rents and estimated monthly expense reimbursements under active leases as of December 31, 2004.  Portfolio annualized rental revenue is annualized rental revenue for our entire portfolio of properties as of a point in time, including both consolidated properties and properties owned through unconsolidated real estate joint ventures as of December 31, 2004.  Information regarding our five largest tenants is set forth below:

(1)          Generally, the leases with the United States Government provide for one-year terms or provide for early termination rights, as discussed below.  The United States Government may terminate its leases if, among other reasons, the United States Congress fails to provide funding. Congress has appropriated funds for these leases through September 2005.

(2)          Includes affiliated companies and organizations.

If any of our five largest tenants fail to make rental payments to us or if the United States Government elects to terminate several of its leases and the space cannot be re-leased on satisfactory terms, there would be an adverse effect on our financial performance and ability to make distributions to our shareholders.

As of December 31, 2004, the United States intelligence and defense industry (comprising the United States Government and intelligence and defense contractors) accounted for approximately 46.8% of our portfolio annualized rental revenue. Most of the 13.1% of our portfolio annualized rental revenue that we derived from leases with agencies of the United States Government as of December 31, 2004 is included in the 46.8% of our portfolio annualized revenue from the United States intelligence and defense industry. We classify the revenue from our leases into industry groupings based solely on management’s knowledge of the tenants’ operations in leased space. Occasionally, classifications require subjective and complex judgments. For example, we have a tenant that is considered by many to be in the computer industry; however, since the nature of that tenant’s operations in

9

the space leased from us is focused on providing service to the United States Government’s intelligence and defense departments, we classify the revenue we earn from the lease as United States intelligence and defense industry revenue. We do not use independent sources such as Standard Industrial Classification codes for classifying our revenue into industry groupings and if we did, the resulting groupings would be materially different.

We have become increasingly reliant on intelligence and defense industry tenants, particularly due to the increased activity in those sectors following the events of September 11, 2001. Furthermore, we expect that the percentage of our portfolio annualized rental revenue derived from the intelligence and defense industry will continue to increase. A reduction in government spending for intelligence and defense could affect the ability of these tenants to fulfill lease obligations or decrease the likelihood that these tenants will renew their leases. In the case of the United States Government, a reduction in government spending could result in the early termination of leases. Such occurrences could have an adverse effect on our results of operations, financial condition, cash flows and ability to make distributions to our shareholders.

We rely on the ability of our tenants to pay rent and would be harmed by their inability to do so.  Our performance depends on the ability of our tenants to fulfill their lease obligations by paying their rental payments in a timely manner.  In addition, as noted above, we rely on a few major tenants for a large percentage of our total rental revenue.  If one of our major tenants, or a number of our smaller tenants, were to experience financial difficulties, including bankruptcy, insolvency or general downturn of business, there could be an adverse effect on our financial performance and ability to make expected distributions to shareholders.

Our properties are geographically concentrated in the Mid-Atlantic region, particularly in the Baltimore/Washington Corridor. We may suffer economic harm in the event of a decline in the real estate market or general economic conditions in that region.  All of our properties are located in the Mid-Atlantic region of the United States, and as of December 31, 2004, our properties located in the Baltimore/Washington Corridor accounted for 48.7% of our total annualized rental revenue.  Our properties are also typically concentrated in office parks in which we own most of the properties.  Consequently, we do not have a broad geographic distribution of our properties.  As a result, a decline in the real estate market or general economic conditions in the Mid-Atlantic region, the Baltimore/Washington Corridor or the office parks in which our properties are located could have an adverse effect on our financial position, results of operations, cash flows and ability to make expected distributions to our shareholders.

We believe that the economic slowdown in the United States over the last three years adversely affected occupancy rates in the Mid-Atlantic region and our properties and, in turn, led to downward pressure on rental rates.  Lower occupancy rates and the resulting increased competition for tenants in our operating regions placed downward pressure on rental rates in most of these regions, a trend that may affect us further as we attempt to lease vacant space and renew leases scheduled to expire on occupied space.  As a result, we may have difficulty leasing both existing vacant space and space associated with future lease expirations at rental rates that are sufficient to meet our short term capital needs, which could adversely affect our financial position, results of operations, cash flows and ability to make distributions to shareholders.

We would suffer economic harm if we were unable to renew our leases on favorable terms.  When leases expire for our properties, our tenants may not renew or may renew on terms less favorable to us than the terms of their original leases.  If a tenant leaves, we can expect to experience a vacancy for some period of time, as well as higher capital costs than if a tenant renews.  As a result, our financial performance and ability to make expected distributions to our shareholders could be adversely affected if we experience a high volume of tenant departures at the end of their lease terms.  Set forth below are the percentages of portfolio annualized rental revenue as of December 31, 2004 that were subject to scheduled lease expirations in each of the next five years:

Most of the leases with our largest tenant, the United States Government, which account for 13.1% of our annualized rental revenue at December 31, 2004, provide for consecutive one-year terms or provide for early termination rights.  All of the leasing statistics set forth above assume that the United States Government will remain in the space that it leases through the end of the respective arrangements, without ending consecutive one-year leases pre-maturely or exercising early termination

10

rights.  We reported the statistics in this manner since we manage our leasing activities using these same assumptions and believe these assumptions to be probable.

We may not be able to compete successfully with other entities that operate in our industry. The commercial real estate market is highly competitive. We compete for the purchase of commercial property with many entities, including other publicly traded commercial REITs. Many of our competitors have substantially greater financial resources than we do. If our competitors prevent us from buying properties that we target for acquisition, we may not be able to meet our property acquisition and development goals. Moreover, numerous commercial properties compete for tenants with our properties. Some of the properties competing with ours may have newer or more desirable locations, or the competing properties’ owners may be willing to accept lower rates than are acceptable to us. Competition for property acquisitions, or for tenants in properties that we own, could have an adverse effect on our financial performance and distributions to our shareholders.

We may be unable to execute our plans to acquire existing commercial real estate properties. We intend to acquire existing commercial real estate properties to the extent that suitable acquisitions can be made on advantageous terms. Acquisitions of commercial properties entail risks, such as the risks that we may not be in a position or have the opportunity in the future to make suitable property acquisitions on advantageous terms and that such acquisitions will fail to perform as expected.  Our failure to successfully execute acquisitions of existing real estate properties could adversely affect our financial performance and our ability to make distributions to our shareholders.

We may suffer economic harm as a result making unsuccessful acquisitions in new markets.  We may from time to time pursue selective acquisitions outside of the Mid-Atlantic region, expanding into regions where we do not currently have properties.  These acquisitions may entail risks in addition to those we have faced in past acquisitions, such as the risk that we do not correctly anticipate conditions or trends in a new region, and are therefore not able to operate the acquired property profitably.  If this occurred, it could adversely affect our financial performance and our ability to make distributions to our shareholders.

We may be unable to execute our plans to develop and construct additional properties.  Although the majority of our investments are in currently leased properties, we also develop and construct properties, including some that are not fully pre-leased. When we develop and construct properties, we assume the risk that actual costs will exceed our budgets, that we will experience construction or development delays and that projected leasing will not occur, any of which could adversely affect our financial performance and our ability to make distributions to our shareholders. In addition, we generally do not obtain construction financing commitments until the development stage of a project is complete and construction is about to commence. We may find that we are unable to obtain financing needed to continue with the construction activities for such projects.

We may suffer economic harm as a result of the actions of our joint venture partners.  We invest in certain entities in which we are not the exclusive investor or principal decision maker.  As of December 31, 2004, we owned two operating properties and two development/construction properties through joint ventures.  We also continue to pursue new investments in real estate through joint ventures.  Aside from our inability to unilaterally control the operations of joint ventures, our investments in joint ventures entail the additional risks that (i) the other parties to these investments may not fulfill their financial obligations as investors, in which case we may need to fund such parties’ share of additional capital requirements and (ii) the other parties to these investments may take actions that are inconsistent with our objectives, either of which could have an adverse effect on our financial condition, results of operations, cash flows and ability to make expected distributions to our shareholders.

We are subject to possible environmental liabilities.  We are subject to various Federal, state and local environmental laws.  These laws can impose liability on property owners or operators for the costs of removal or remediation of hazardous substances released on a property, even if the property owner was not responsible for the release of the hazardous substances.  Costs resulting from environmental liability could be substantial.  The presence of hazardous substances on our properties may also adversely affect occupancy and our ability to sell or borrow against those properties. In addition to the costs of government claims under environmental laws, private plaintiffs may bring claims for personal injury or other reasons.  Additionally, various laws impose liability for the costs of removal or remediation of hazardous substances at the disposal or treatment facility.  Anyone who arranges for the disposal or treatment of hazardous substances at such a facility is potentially liable under such laws.  These laws often impose liability on an entity even if the facility was not owned or operated by the entity.

Real estate investments are illiquid, and we may not be able to sell our properties on a timely basis when we determine it is appropriate to do so.  Real estate investments can be difficult to sell and convert to cash quickly, especially if market conditions are depressed.  Such illiquidity will tend to limit our ability to vary our portfolio of properties promptly in

11

response to changes in economic or other conditions.  Moreover, under certain circumstances, the Internal Revenue Code imposes certain penalties on a REIT that sells property held for less than four years. In addition, for certain of our properties that we acquired by issuing units in our Operating Partnership, we are restricted by agreements with the sellers of the properties for a certain period of time from entering into transactions (such as the sale or refinancing of the acquired property) that will result in a taxable gain to the sellers without the seller’s consent .  Due to all of these factors, we may be unable to sell a property at an advantageous time.

We are subject to other possible liabilities that would adversely affect our financial position and cash flows.  Our properties may be subject to other risks related to current or future laws, including laws benefiting disabled persons, and state or local laws relating to zoning, construction and other matters.  These laws may require significant property modifications in the future for which we may not have budgeted and could result in the levy of fines against us.  In addition, although we believe that we adequately insure our properties, we are subject to the risk that our insurance may not cover all of the costs to restore a property that is damaged by a fire or other catastrophic events, including acts of war or terrorism.  The occurrence of any of these events could have an adverse effect on our financial condition, results of operations, cash flows and ability to make expected distributions to our shareholders.

As a result of the September 11, 2001 terrorist attacks, we may be subject to increased costs of insurance and limitations on coverage. Our portfolio of properties is insured for losses under our property, casualty and umbrella insurance policies through September 2005.  These policies include coverage for acts of terrorism.  Due largely to the terrorist attacks on September 11, 2001, the insurance industry changed its risk assessment approach and pricing structure.  Continuing changes in the insurance industry may increase the cost of insuring our properties and decrease the scope of insurance coverage, either of which could adversely affect our financial position and operating results.

We may suffer adverse effects as a result of the indebtedness that we carry and the terms and covenants that relate to this debt.  Our strategy is to operate with slightly higher debt levels than many other REITs.  However, these higher debt levels could make it difficult to obtain additional financing when required and could also make us more vulnerable to an economic downturn.  Most of our properties have been mortgaged to collateralize indebtedness.  In addition, we rely on borrowings to fund some or all of the costs of new property acquisitions, construction and development activities and other items.  Our organizational documents do not limit the amount of indebtedness that we may incur.  As of December 31, 2004, our total outstanding debt was $1.0 billion and our debt to total assets (defined as mortgage loans divided by total assets) was 59.0%.

Payments of principal and interest on our debt may leave us with insufficient cash to operate our properties or pay distributions to our shareholders required to maintain our qualification as a REIT.  We are also subject to the risks that:

•                  we may not be able to refinance our existing indebtedness or refinance on terms as favorable as the terms of our existing indebtedness;

•                  certain debt agreements of our Operating Partnership could restrict the ability of our Operating Partnership to make cash distributions to us, which could result in reduced distributions to our shareholders or the need to incur additional debt to fund these distributions; and

•                  if we are unable to pay our debt service on time or are unable to comply with restrictive financial covenants in certain of our mortgage loans, our lenders could foreclose on our properties securing such debt and in some cases other properties and assets that we own.

A number of our loans are cross-collateralized, which means that separate groups of properties from our portfolio secure each of these loans.  More importantly, many of our loans are cross-defaulted, which means that failure to pay interest or principal on any of our loans will create a default on certain of our other loans.  Any foreclosure of our properties would result in loss of income and asset value that would negatively affect our financial condition, results of operations, cash flows and ability to make expected distributions to our shareholders.  In addition, if we are in default and the value of the properties securing a loan is less than the loan balance, the lender may require payment from our other assets.

As of December 31, 2004, approximately 27.8% of our total debt had variable interest rates.  If short-term interest rates were to rise, our debt service payments on adjustable rate debt would increase, which would lower our net income and could decrease our distributions to our shareholders.   We use interest rate swap agreements from time to time to reduce the impact of changes in interest rates. Decreases in interest rates would result in increased interest payments due under interest rate swap agreements in place and could result in the Company recognizing a loss and remitting a payment to unwind such agreements.

12

We must refinance our mortgage debt in the future.  As of December 31, 2004, our scheduled debt payments over the next five years, including maturities, were as follows:

(1)          Represents principal maturities only and therefore excludes premiums and discounts.

(2)          Includes maturities totaling $261.4 million that may be extended for one-year periods, subject to certain conditions.

Our operations likely will not generate enough cash flow to repay some or all of this debt without additional borrowings or new equity financings.  If we cannot refinance our debt, extend the repayment dates, or raise additional equity prior to the date when our debt matures, we would default on our existing debt, which would have an adverse effect on our financial position, results of operations, cash flows and ability to make expected distributions to our shareholders.

We may be unable to continue to make shareholder distributions at expected levels.  We intend to make regular quarterly cash distributions to our shareholders.  However, distribution levels depend on a number of factors, some of which are beyond our control.

Our loan agreements contain provisions that could restrict future distributions.  Our ability to sustain our current distribution level will also be dependent, in part, on other matters, including:

•                  continued property occupancy and timely payment by tenants of rent obligations;

•                  the amount of future capital expenditures and expenses relating to our properties;

•                  the level of leasing activity and future rental rates;

•                  the strength of the commercial real estate market;

•                  competition;

•                  the costs of compliance with environmental and other laws;

•                  our corporate overhead levels;

•                  the amount of uninsured losses; and

•                  our decision to reinvest in operations rather than distribute available cash.

In addition, we can make distributions to the holders of our common shares only after we make preferential distributions to holders of our preferred shares.

Our ownership limits are important factors.  Our Declaration of Trust limits ownership of our common shares by any single shareholder to 9.8% of the number of the outstanding common shares or 9.8% of the value of the outstanding common shares, whichever is more restrictive.  Our Declaration of Trust also limits ownership by any single shareholder of our common and preferred shares in the aggregate to 9.8% of the aggregate value of the outstanding common and preferred shares.  We call these restrictions the “Ownership Limit.” Our Declaration of Trust allows our Board of Trustees to exempt shareholders from the Ownership Limit, and our Board of Trustees previously has exempted one entity from the Ownership Limit.

Our Declaration of Trust includes other provisions that may prevent or delay a change of control.  Subject to the requirements of the New York Stock Exchange, our Board of Trustees has the authority, without shareholder approval, to issue additional securities on terms that could delay or prevent a change in control.  In addition, our Board of Trustees has the authority to reclassify any of our unissued common shares into preferred shares.  Our Board of Trustees may issue preferred shares with such preferences, rights, powers and restrictions as our Board of Trustees may determine, which could also delay or prevent a change in control.

Our Board of Trustees is divided into three classes of Trustees, which could delay a change of control.  Our Declaration of Trust divides our Board of Trustees into three classes.  The term of one class of the Trustees expires each year, at

13

which time a successor class is elected for a term ending at the third succeeding annual meeting of shareholders.  Such staggered terms make it more difficult for a third party to acquire control of us.

The Maryland business statutes also impose potential restrictions on a change of control of our company.  Various Maryland laws may have the effect of discouraging offers to acquire us, even if the acquisition would be advantageous to shareholders.  Our bylaws exempt us from such laws, but our Board of Trustees can change our bylaws at any time to make these provisions applicable to us.

Our failure to qualify as a REIT would have adverse tax consequences.  We believe that since 1992 we have qualified for taxation as a REIT for Federal income tax purposes.  We plan to continue to meet the requirements for taxation as a REIT.  Many of these requirements, however, are highly technical and complex.  The determination that we are a REIT requires an analysis of various factual matters and circumstances that may not be totally within our control. For example, to qualify as a REIT, at least 95% of our gross income must come from certain sources that are itemized in the REIT tax laws.  We are also required to distribute to shareholders at least 90% of our REIT taxable income (excluding capital gains).  The fact that we hold most of our assets through our Operating Partnership and its subsidiaries further complicates the application of the REIT requirements.  Even a technical or inadvertent mistake could jeopardize our REIT status.  Furthermore, Congress and the Internal Revenue Service might make changes to the tax laws and regulations and the courts might issue new rulings that make it more difficult or impossible for us to remain qualified as a REIT.

If we fail to qualify as a REIT, we would be subject to Federal income tax at regular corporate rates.  Also, unless the Internal Revenue Service granted us relief under certain statutory provisions, we would remain disqualified as a REIT for four years following the year we first fail to qualify.  If we fail to qualify as a REIT, we would have to pay significant income taxes and would therefore have less money available for investments or for distributions to our shareholders.  This would likely have a significant adverse effect on the value of our securities.  In addition, we would no longer be required to make any distributions to our shareholders.

We have certain distribution requirements that reduce cash available for other business purposes.  As a REIT, we must distribute 90% of our annual taxable income (excluding capital gains), which limits the amount of cash we have available for other business purposes, including amounts to fund our growth.  Also, it is possible that because of the differences between the time we actually receive revenue or pay expenses and the period during which we report those items for distribution purposes, we may have to borrow funds to meet the 90% distribution requirement.  We may become subject to tax liabilities that adversely affect our operating cash flow and available cash for distribution to shareholders.

A number of factors could cause our security prices to decline.  As is the case with any publicly-traded securities, certain factors outside of our control could influence the value of our common and preferred shares.  These conditions include, but are not limited to:

•                  market perception of REITs in general and office REITs in particular;

•                  market perception of REITs relative to other investment opportunities;

•                  the level of institutional investor interest in our company;

•                  general economic and business conditions;

•                  prevailing interest rates; and

•                  market perception of our financial condition, performance, dividends and growth potential.

Generally, REITs are tax-advantaged relative to C corporations because they are not subject to corporate-level federal income tax on income that they distribute to shareholders. However, Congress recently made changes to the tax laws and regulations that could make it less advantageous for investors to invest in REITs. The Jobs and Growth Tax Relief Reconciliation Act of 2003, or the 2003 Act, provides that generally for taxable years beginning after December 31, 2002 and before December 31, 2008, certain dividends received by domestic individual shareholders from certain C corporations are subject to a reduced rate of tax of up to 15%. Prior to this Act, such dividends received by domestic individual shareholders were generally subject to tax at ordinary income rates, which were as high as 38.6%. In general, the provisions of the Act do not benefit individual shareholders of REITs and could make an investment in a C corporation that is not a REIT more attractive than an investment in a REIT. We cannot predict the effects that this Act may have on the market price for our common or preferred shares.

14

The average daily trading volume of our common shares during 2004 was approximately 147,000 shares, and the average trading volume of our publicly-traded preferred shares is generally insignificant.  As a result, relatively small volumes of transactions could have a pronounced effect on the market price of such shares.

We are dependent on external sources of capital for future growth.  As noted above, because we are a REIT, we must distribute at least 90% of our annual taxable income to our shareholders.  Due to this requirement, we will not be able to fund our acquisition, construction and development activities using cash flow from operations.  Therefore, our ability to fund these activities is dependent on our ability to access capital funded by third parties.  Such capital could be in the form of new loans, equity issuances of common shares, preferred shares, common and preferred units in our Operating Partnership or joint venture funding.  Such capital may not be available on favorable terms or at all.  Moreover, additional debt financing may substantially increase our leverage and subject us to covenants that restrict management’s flexibility in directing our operations, and additional equity offerings may result in substantial dilution of our shareholders’ interests.  Our inability to obtain capital when needed could have a material adverse effect on our ability to expand our business and fund other cash requirements.

Our business and operations would suffer in the event of system failures.  Despite system redundancy, the implementation of security measures and the existence of a Disaster Recovery Plan for our internal information technology systems, our systems are vulnerable to damages from computer viruses, unauthorized access, energy blackouts, natural disasters, terrorism, war and telecommunication failures. Any system failure or accident that causes interruptions in our operations could result in a material disruption to our business. We may also incur additional costs to remedy damages caused by such disruptions.

Certain of our officers and Trustees have potential conflicts of interest.  Certain of our officers and members of our Board of Trustees own partnership units in our Operating Partnership.  These individuals may have personal interests that conflict with the interests of our shareholders.  For example, if our Operating Partnership sells or refinances certain of the properties that these officers or Trustees contributed to the Operating Partnership, the officers or Trustees could suffer adverse tax consequences.  Their personal interests could conflict with our interests if such a sale or refinancing would be advantageous to us.  We have certain policies in place that are designed to minimize conflicts of interest.  We cannot assure you, however, that these policies will be successful in eliminating the influence of such conflicts, and if they are not successful, decisions could be made that might fail to reflect fully the interests of all of our shareholders.

We are dependent on our key personnel, and the loss of any key personnel could have an adverse effect on our operations.  We are dependent on the efforts of our executive officers.  The loss of any of their services could have an adverse effect on our operations.  Although certain of our officers have entered into employment agreements with us, we cannot assure you that they will remain employed with us.

We may change our policies without shareholder approval, which could adversely affect our financial condition, results of operations, market price of our common shares or ability to pay distributions.  Our Board of Trustees determines all of our policies, including our investment, financing and distribution policies.  Although our Board of Trustees has no current plans to do so, it may amend or revise these policies at any time without a vote of our shareholders.  Policy changes could adversely affect our financial condition, results of operations, the market price of our securities or distributions.

Compliance with changing regulation of corporate governance and public disclosure may result in additional expenses, affect our operations and affect our reputation.  Changing laws, regulations and standards relating to corporate governance and public disclosure, including the Sarbanes-Oxley Act of 2002 and new SEC regulations and New York Stock Exchange rules, are creating uncertainty for public companies. These new or changed laws, regulations and standards are subject to varying interpretations in many cases due to their lack of specificity, and as a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies, which could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and governance practices. We are committed to maintaining high standards of corporate governance and public disclosure. As a result, our efforts to comply with evolving laws, regulations and standards have resulted in, and are likely to continue to result in, increased general and administrative expenses and a diversion of management time and attention from revenue-generating activities to compliance activities. In particular, our efforts to comply with Section 404 of the Sarbanes-Oxley Act of 2002 and the related regulations regarding our required assessment of our internal controls over financial reporting and our external auditors’ audit of that assessment has required the commitment of significant financial and managerial resources. In addition, it has become more difficult and more expensive for us to obtain director and officer liability insurance. We expect these efforts to require the continued commitment of significant resources. Further, our trustees, Chief Executive Officer, Chief Operating Officer and Chief Financial Officer could face an increased risk of personal liability in connection with the performance of their duties. As a result,

15

Item 2.  Properties

The following table provides certain information about our office properties as of December 31, 2004:

17