SEC Form DEFA14A filed by Builders FirstSource Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No. )

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☐ Preliminary Proxy Statement

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☐ Definitive Proxy Statement

☒ Definitive Additional Materials

☐ Soliciting Material under § 240.14a-12

Builders FirstSource, Inc.

(Name of registrant as specified in its charter)

(Name of person(s) filing proxy statement, if other than the registrant)

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Builders FirstSource P.O. BOX 8016, CARY, NC 27512-9903 Your vote matters! Builders FirstSource, Inc. Annual Meeting of Stockholders Tuesday, May 27, 2025 9:00 AM, Central Time 6031 Connection Drive, Irving TX 75039 Meeting Materials: Notice of Meeting and Proxy Statement & Annual Report or Form 10-K Important Notice Regarding the Availability of Proxy Materials for the Stockholders Meeting To Be Held On May 27, 2025 For Stockholders of record as of March 28, 2025 To order paper materials, use one of the following methods. For a convenient way to view proxy materials, VOTE, and obtain directions to attend the meeting go to www.proxydocs.com/BLDR To vote your proxy while visiting this site, you will need the 12 digit control number in the box below. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. This is not a ballot. You cannot use this notice to vote your shares. We encourage you to access and review all of the important information contained in the proxy materials before voting. Under United States Securities and Exchange Commission rules, proxy materials do not have to be delivered in paper. Proxy materials can be distributed by making them available on the internet. If you want to receive a paper or e-mail copy of the proxy materials, you must request one. There is no charge to you for requesting a copy. In order to receive a paper package in time for this year's meeting, you must make this request on or before May 16, 2025. Internet: www.investorelections.com/BLDR Call: 1-866-648-8133 Email: [email protected] * If requesting material by e-mail, please send a blank e-mail with the 12 digit control number (located below) in the subject line. No other requests, instructions OR other inquiries should be included with your e-mail requesting material. Your control number Have the 12 digit control number located in the box above available when you access the website and follow the instructions. SEE REVERSE FOR FULL AGENDA Copyright © 2025 BetaNXT, Inc. or its affiliates. All Rights Reserved

Builders® FirstSource THE BOARD OF DIRECTORS RECOMMENDS A VOTE: FOR ON PROPOSALS 1, 2, 3, 4, 5 AND 6 PROPOSAL 1. Election of Directors 1.01 Mark A. Alexander نه 1.02 Dirkson R. Charles 1.03 Peter M. Jackson Builders FirstSource, Inc. Annual Meeting of Stockholders An advisory vote on the compensation of the named executive officers 3. The ratification of PricewaterhouseCoopers LLP as our independent registered public accounting firm 4. An amendment to the Certificate of Incorporation to declassify the Board of Directors 5. An amendment to the Certificate of Incorporation to remove limits on the size of our Board of Directors 6. An amendment to the Certificate of Incorporation to limit the liability of certain officers consistent with Delaware law