Form 4 Filing for William B. Hayes

This Form 4 filing reports a transaction by William B. Hayes, a director at Builders FirstSource, Inc. On September 10, 2026, Mr. Hayes acquired 583 shares of common stock under the company's 2026 Incentive Plan, in lieu of cash compensation. This acquisition is part of the Corporation's Amended and Restated Director Compensation Policy. Following this transaction, Mr. Hayes directly owns 20,221 shares. Additionally, he has indirect ownership of 14,593 shares held by a Spousal Lifetime Access Trust. The filing was signed by Alena Brenner, by power of attorney, on September 14, 2026.