#1 Reflects grant of restricted stock units (RSUs) which vest in three approximately equal installments on each of the three anniversaries of the grant date.

#1 In connection with the vesting on August 16, 2024, of 1,355 restricted stock units previously granted to Mrs. Hickox, Mrs. Hickox's receipt of 1,355 shares of common stock was deferred resulting in Mrs. Hickox's receipt instead of 1,355 shares of deferred stock units into the First Financial Bankshares, Inc. Supplemental Executive Retirement Plan, as amended and restated effective July 26, 2022 (the "SERP"). Mrs. Hickox is therefore reporting the disposition of 1,355 restricted stock units in exchange for an equal number of shares of deferred stock units under the SERP, which are payable upon Mrs. Hickox's termination of employment.