Corporate Office Properties Trust Forms Joint Venture and Acquires Two Buildings for Redevelopment.

COLUMBIA, Md. -- Corporate Office Properties Trust (COPT) (NYSE: OFC) announced today the formation of a joint venture with Opportunity Invest, LLC, a redevelopment company headed by CEO Richard Previdi and his partners John Graham and William Rand that has offices in Maryland, New Jersey and Boston. The purpose of the joint venture is to acquire warehouse properties primarily within COPT's core Greater Washington DC submarkets that will be redeveloped into Class A office space. The joint venture will be known as COPT Opportunity Invest I, LLC, and COPT will own an 80% to 93% interest in each property acquired by the venture. Opportunity Invest is responsible for sourcing acquisitions, providing redevelopment and construction management services, and leasing. COPT will arrange the debt to finance each asset, provide any necessary loan guarantees, provide property management services, and have an option to purchase the properties at a discount to market. COPT initially invested $900,000 and Opportunity Invest invested $100,000 at the formation of the joint venture. The first phase of the program will invest up to $300.0 million cumulatively in a series of acquisitions. The joint venture has closed on two acquisitions. The acquisitions were initially financed through COPT's unsecured line of credit and will ultimately be financed through construction loans. Upon stabilization, the joint venture assets will either be purchased by COPT for its wholly owned portfolio or sold. E[acute accent]The first acquisition is a sale and partial leaseback of a 140,000 square foot property comprised of a 61,000 square foot two-story office building with an attached 79,000 square foot, single story warehouse building that will be converted to office space. The purchase price was $12.0 million, and the property is located at the intersection of Route 28 and McLearen Road across from the Dulles Airport, in Herndon, Virginia. The joint venture acquired the building from Hubbell, Inc, and it is the headquarters for the Hubbell Inc. subsidiary, Pulse Communications, Inc. ("Pulsecom"). Pulsecom will lease back approximately 78,000 square feet of the existing space for five years. In addition to the existing property, the joint venture plans to build 55,000 square feet of new warehouse space on the site that will be leased or sold as condominiums. The total cost for the new warehouse space and renovation of existing space is projected to be an additional $10.0 million and the property is expected to be completed and leased within 24 months. E[acute accent]The joint venture's second acquisition is a 472,000 square foot warehouse building on a 19 acre site located at 7468 Candlewood Road in the Baltimore Commons Business Park in Hanover, Maryland. The property is a former distribution facility for Michelin North America, Inc. that will be converted to 325,000 square feet of Class A office space. The purchase price was $18.8 million and total renovation and leasing costs are projected to be an additional $33.6 million, with completion and lease-up projected to take 30 months. Renovation plans include splitting the existing building into two buildings and creating interior courtyards within each building. Upon completion, the space will be marketed as a lower cost alternative to Class A space located in surrounding suburban Class A office parks as a single user or multi-tenanted property. E[acute accent]"We are pleased to announce the formation of this joint venture with Opportunity Invest which will allow the Company to invest in redevelopment properties that we would typically not have an opportunity to own. We believe there is demand for this product type and price point in our markets, which further solidifies our strong market position," stated Randall M. Griffin, President and Chief Executive Officer for Corporate Office Properties Trust. "We are also excited to announce that the joint venture is kicking off with two acquisitions, both located in our core markets and in close proximity to buildings in our existing portfolio," he added.

E[acute accent]Company Information

E[acute accent]Corporate Office Properties Trust (COPT) is a fully integrated, self-managed real estate investment trust (REIT) that focuses on the ownership, management, leasing, acquisition and development of suburban office properties primarily in select Mid-Atlantic submarkets. The Company is among the largest owners of suburban office properties in the Greater Washington, DC region. The Company currently owns 162 office properties totaling 14.0 million rentable square feet, which includes 20 properties totaling 1.5 million rentable square feet held through joint ventures. The Company has implemented a core customer expansion strategy that is built around meeting, through acquisitions and development, the multi-location requirements of the Company's existing strategic tenants. The Company's property management services team provides comprehensive property and asset management to company owned properties and select third party clients. The Company's development and construction services team provides a wide range of development and construction management services for company owned properties, as well as land planning, design/build services, consulting, and merchant development to select third party clients. The Company's shares are traded on the New York Stock Exchange under the symbol OFC. More information on Corporate Office Properties Trust can be found on the Internet at www.copt.com.

E[acute accent]Forward-Looking Information

E[acute accent]This press release may contain "forward-looking" statements, as defined in Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, that are based on the Company's current expectations, estimates and projections about future events and financial trends affecting the Company. Forward-looking statements can be identified by the use of words such as "may", "will", "should", "expect", "estimate" or other comparable terminology. Forward-looking statements are inherently subject to risks and uncertainties, many of which the Company cannot predict with accuracy and some of which the Company might not even anticipate. Accordingly, the Company can give no assurance that these expectations, estimates and projections will be achieved. Future events and actual results may differ materially from those discussed in the forward-looking statements. E[acute accent]Important factors that may affect these expectations, estimates, and projections include, but are not limited to:

E[acute accent]--the Company's ability to borrow on favorable terms;

E[acute accent]--general economic and business conditions, which will, among other things, affect office property demand and rents, tenant creditworthiness, interest rates and financing availability;

E[acute accent]--adverse changes in the real estate markets including, among other things, increased competition with other companies;

E[acute accent]--risk of real estate acquisition and development, including, among other things, risks that development projects may not be completed on schedule, that tenants may not take occupancy or pay rent or that development or operating costs may be greater than anticipated;

E[acute accent]--risks of investing through joint venture structures, including risks that the Company's joint venture partners may not fulfill their financial obligations as investors or may take actions that are inconsistent with the Company's objectives;

E[acute accent]--our ability to satisfy and operate effectively under federal income tax rules relating to real estate investment trusts and partnerships;

E[acute accent]--governmental actions and initiatives; and

E[acute accent]--environmental requirements.

E[acute accent]The Company undertakes no obligation to update or supplement any forward-looking statements. For further information, please refer to the Company's filings with the Securities and Exchange Commission, particularly the section entitled "Risk Factors" in Item 1 of the Company's Annual Report on Form 10-K for the year ended December 31, 2004.