X0306 4 2022-02-23 0000354190 Arthur J. Gallagher & Co. AJG 0001222374 HOWELL DOUGLAS K 2850 GOLF ROAD ROLLING MEADOWS IL 60008-4002 1 VP & Chief Financial Officer Notional Stock Units 0 2022-02-23 4 A 0 726.92 153.73 A Common Stock 726.92 206624.16 D Each notional stock unit represents a right to receive one share of Gallagher common stock. Portions of these notional stock units are payable to the reporting person in shares of common stock in July of 2021, 2022, 2023, 2025 and 2026 and following the reporting person's separation from service. /s/ Seth Diehl, by power of attorney 2022-02-25