Leidos Holdings, Inc.

As permitted by the rules of the SEC, we are using the internet as a means of furnishing proxy materials to our stockholders. We believe that this method will make the proxy distribution process more efficient, lower costs and help in conserving natural resources.

On or about March 19, 2026, we mailed to our stockholders a Notice of Internet Availability of Proxy Materials containing instructions on how to access our proxy materials, including our proxy statement and annual report. The Notice of Internet Availability of Proxy Materials also instructs you on how to access your proxy or voting instruction card to be able to vote through the internet or by telephone. Other stockholders, in accordance with their prior requests, and employees with regular access to email have received email notification of how to access our proxy materials and vote via the internet or by telephone or have been mailed paper copies of our proxy materials or a proxy and voting instruction card.

Important Notice Regarding the Availability of Proxy Materials for the Annual Stockholders Meeting to Be Held on May 1, 2026.

The proxy statement and annual report are available atwww.proxyvote.com.

Information and reports on our website to which we refer in this proxy statement will not be deemed a part of, or otherwise incorporated by reference into, this proxy statement.