X0609 4 2026-08-14 0000036029 FIRST FINANCIAL BANKSHARES INC FFIN 0001243211 DUESER F SCOTT false P. O. BOX 701 ABILENE TX 79604-0701 true true false false Executive Chairman false Common Stock 2026-08-14 4 A false 12755 0 A 515262 I By Trust Common Stock 2026-08-14 4 D false 8875 D 506387 I By Trust Common Stock 471004 I By Partnership Common Stock 408310 I By Partnership Deferred Stock Units 2026-08-14 4 A false 8875 A Common Stock 8875 59245 D Reflects grant of restricted stock units (RSUs) which vest in three approximately equal installments on each of the three anniversaries of the grant date. Represents shares held by several trusts of which Mr. Dueser is trustee, settlor and beneficiary. In connection with the vesting on August 14, 2026, of 8,875 restricted stock units previously granted to the reporting person, the reporting person's receipt of 8,875 shares of common stock was deferred resulting in the reporting person's receipt instead of 8,875 shares of deferred stock units into the First Financial Bankshares, Inc. Supplemental Executive Retirement Plan, as amended and restated effected July 26, 2022 (the "SERP"). The reporting person is therefore reporting the disposition of 8,875 restricted stock units in exchange for an equal number of deferred stock units under the SERP, which are payable upon the reporting person's termination. Represents shares that are owned by a family limited partnership of which Mr. Dueser serves as manager of the general partner and to which he disclaims beneficial ownership with respect to 353,253 shares. This report should not be deemed an admission that Mr. Dueser is the beneficial owner of these shares for purposes of Section 16 or any other purpose. Represents shares that are owned by a family limited partnership of which Mr. Dueser serves as manager of the general partner and to which he disclaims beneficial ownership with respect to 291,125 shares. This report should not be deemed an admission that Mr. Dueser is the beneficial owner of these shares for purposes of Section 16 or any other purpose. By: Michelle S. Hickox Attorney in Fact for F. Scott Dueser 2026-08-18