Corporate Office Properties Trust Acquires 404,665 Square Foot Office Building.

Business Editors

COLUMBIA, Md.--(BUSINESS WIRE)--June 3, 2003

Corporate Office Properties Trust (NYSE:OFC), the largest owner of commercial office properties in the Baltimore/Washington Corridor, announced today the $71.2 million acquisition of 13200 Woodland Park Drive, a 404,665 square foot Class A office building located in Herndon, Virginia.

The thirteen-story building is presently 100% leased by VeriSign, Inc., a provider of infrastructure services for the Internet and telecommunications networks. The acquisition was funded by the recent sale of 5,290,000 common shares of beneficial interest, which generated approximately $79.5 million in net proceeds to the Company.

The acquisition increases Corporate Office Properties' ownership in the Northern Virginia/Dulles Toll Road sub-market to approximately 1.2 million square feet of Class A office space. The Northern Virginia portfolio is presently 94% leased.

13200 Woodland Park Drive is located within the Woodlands Office Park at the Centreville Road exit of the Dulles Toll Road, and is less than three miles from Dulles International Airport. The purchase includes an adjacent 1,575 space parking garage.

Under the terms of the transaction, VeriSign exercised its option to acquire the property, assigned the purchase option to Corporate Office Properties, and agreed to the continued long-term leasing of the building, while phasing out of a portion of their space beginning in June 2005 through September 2006.

"Northern Virginia represents an important growth market for the Company, and we continue to pursue acquisition and development opportunities that can further strengthen our growing position in the region," stated Randall M. Griffin, President and Chief Operating Officer of Corporate Office Properties Trust. "This building is a key addition to our portfolio given its high quality profile and strategic position in the Dulles sub-market, coupled with the long-term commitment of VeriSign, a recognized industry leader. The transaction exemplifies our strategy of creating a critical mass of properties in Northern Virginia that will allow the Company to continue meeting the needs of our existing tenant base," he added.

"This transaction is unusual, in that it is a genuine win-win for all parties. VeriSign is able to meet its sizeable current and future growth needs for space in Northern Virginia, while lowering its operating costs. Tishman Speyer Properties realizes its vision for the Waterview development, and Corporate Office Properties gains a significant presence in the area, in a beautiful landmark building," said Jade Dauser, Director of Purchasing, VeriSign.

"As one of the larger transactions in Northern Virginia this year, we are pleased to have orchestrated this unique arrangement, involving VeriSign, Corporate Office Properties Trust and Tishman Speyer Properties," said Jeff Groh, Executive Vice President, Tenant Representation, Jones Lang LaSalle, who led the negotiations. "A complex transaction requiring the coordination of multiple real estate service disciplines, the sale/leaseback of this well-located property truly benefits all parties. VeriSign is able to substantially reduce its long-term occupancy costs by fully utilizing its original lease rights, while Corporate Office Properties increases its portfolio in Northern Virginia through the purchase of a marquis asset, which is 100% leased. Given its proximity to our nation's Capitol, the fundamentals and recovery expectations of the Northern Virginia office market remain solid."

Company Information

Corporate Office Properties Trust is a fully integrated, self-managed, real estate investment trust which focuses on the ownership, management, leasing, acquisition and development of suburban office properties located in select Mid-Atlantic submarkets.

The Company currently owns 113 office properties totaling 9.5 million rentable square feet, including three properties held through joint ventures. Corporate Development Services, the Company's development company, provides a wide range of development and construction management services.

In addition, Corporate Office Services provides land planning, design/build services, consulting and merchant development to third party entities. 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.

Forward-Looking Information

This press release may contain forward-looking information within the meaning of the Private Litigation Reform Act of 1995. We are making these statements based upon the Company's current best judgment and expectations. Actual results could vary from those presented herein.

The risks and uncertainties associated with the forward-looking information include the strength of the commercial office real estate market in which the Company operates, competitive market conditions, general economic growth, interest rates and capital market conditions.

The Company undertakes no obligations to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. For further information, please refer to the Company's filings with the Securities and Exchange Commission.