COPT DEFENSE PROPERTIES — Director's Dealing 2011

Jul 25, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: CORPORATE OFFICE PROPERTIES TRUST (OFC)
CIK: 0000860546
Period of Report: 2011-07-21

Reporting Person: SHIDLER JAY H (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-07-21	COPLP Units	C	5521	—	Disposed	1821811	Direct
2011-07-21	Common Shares	M	5521	—	Acquired	9521	Direct
2011-07-21	Common Shares	S	5521	$31.96	Disposed	4000	Direct
2011-07-25	COPLP Units	C	5955	—	Disposed	1815856	Direct
2011-07-25	Common Shares	M	5955	—	Acquired	9955	Direct
2011-07-22	Common Shares	S	5955	$31.96	Disposed	4000	Direct

Footnotes

F1: These units were converted into common shares of COPT.

F2: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by Jay H. Shidler on May 12, 2011.

F3: Acquired through conversion of COPLP Units.

F4: These units are owned as follows: 431,893 by Jay H. Shidler and 1,389,918 by Shidler Equities, L.P.

F5: These units are owned as follows: 431,893 by Jay H. Shidler and 1,383,963 by Shidler Equities, L.P.