X0306 5 2018-12-31 0 0 0000354190 GALLAGHER ARTHUR J & CO AJG 0001222374 HOWELL DOUGLAS K 2850 GOLF ROAD ROLLING MEADOWS IL 60008-4002 1 VP & Chief Financial Officer Common Stock 2018-07-10 5 G 0 326 0 A 2605 I By Spouse Common Stock 2018-07-10 5 G 0 326 0 D 42576.6803 D Notional Stock Units 0 2018-12-31 5 I 0 4255 0 A Common Stock 4255 151146 D The reporting person has no voting or invesment power over these shares and disclaims beneficial ownership. Each notional stock unit represents a right to receive one share of Gallagher common stock. In accordance with applicable SEC staff guidance, the reporting person has elected to report periodic investments throughout the year into the Gallagher stock fund under this plan (the Supplemental Savings and Thrift Plan, a nonqualified deferred compensation plan) on an aggregate basis on Form 5. Portions of these notional stock units are payable to the reporting person in shares of common stock in July of 2019, 2020, 2021, 2022, 2023, and following the reporting person's separation from service. /s/ April Hanes-Dowd, by power of attorney 2019-02-14