COPT DEFENSE PROPERTIES

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934 (Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐ Preliminary Proxy Statement

☐Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☒ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material under §240.14a-12

COPT DEFENSE PROPERTIES

(Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

Message from our President +

Chief Executive Officer

Dear Fellow Shareholders,

You are invited to participate in our 2026 Annual Meeting of Shareholders on May 14, 2026, at 9:30 a.m. Eastern Time. We will hold this year’s Annual Meeting virtually through an online webcast, which we believe provides each shareholder an opportunity to meaningfully participate in the Annual Meeting.

During the Annual Meeting, you will have the opportunity to vote on the matters noted below and to submit questions to the Trustees and senior management by visiting www.virtualshareholdermeeting.com/CDP2026. The notice of Annual Meeting and proxy statement accompanying this letter contain further information about the meeting, including the different methods you can use to vote your proxy and how to participate in the meeting.

At this year’s meeting, you will be asked to vote on the following:

•election of eight people to our Board of Trustees;

•approval, on an advisory basis, of the compensation of our named executive officers as disclosed in the proxy statement for this meeting; and

•ratification of PricewaterhouseCoopers LLP’s appointment as our independent registered public accounting firm for the current fiscal year.

Thank you for your continued support of COPT Defense Properties, and I encourage you to participate in our Annual Meeting.

Stephen E. Budorick

President + Chief Executive Officer

Notice of Annual Meeting

of Shareholders

You may vote on these proposals if you were a shareholder of record at the close of business on March 6, 2026.

For information about how to attend and vote at the meeting, see “Questions and Answers—How do I attend the meeting and vote?” in the proxy statement accompanying this notice. Additional information regarding the ability of shareholders to ask questions during the 2026 Annual Meeting, related rules of conduct and other materials for the 2026 Annual Meeting will be available at www.virtualshareholdermeeting.com/CDP2026.

Technical support will be available beginning at 9:00 a.m. Eastern Time on May 14, 2026, through the conclusion of the Annual Meeting by contacting Broadridge at the phone number that will be provided on the website for the virtual meeting.

By order of the Board of Trustees,

David L. Finch

Vice President, General Counsel+ Secretary

YOUR VOTE IS IMPORTANT.

Please consider the issues presented in this Proxy Statement and vote your shares as promptly as possible.

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