UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 ☐ 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 FORM 10-Q (Mark one) COPT DEFENSE PROPERTIES ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 or (Exact name of registrant as specified in its charter) Maryland 23-2947217 (State or other jurisdiction ...