X0609 4 2026-07-01 0000354190 Arthur J. Gallagher & Co. AJG 0001812516 Jain Vishal false 2850 GOLF ROAD ROLLING MEADOWS IL 60008 1 VICE PRESIDENT 0 Common Stock 2026-07-01 4 M 0 2162.694 229.57 A 68903.384 D Common Stock 491.113 I Gallagher 401(k) plan account Notional Stock Units 0 2026-07-01 4 M 0 2162.694 0 D Common Stock 2162.694 9725.8456 D Phantom Stock Common Stock 39710.185 39710.185 D Non-qualified Stock Option 228.20 2033-03-01 Common Stock 14319 14319 D Non-qualified Stock Option 127.90 2028-03-16 Common Stock 13580 13580 D Non-qualified Stock Option 86.17 2027-03-12 Common Stock 10450 10450 D Non-qualified Stock Option 158.56 2029-03-15 Common Stock 9950 9950 D Non-qualified Stock Option 337.74 2032-03-01 Common Stock 9587 9587 D Non-qualified Stock Option 243.54 2031-03-01 Common Stock 8707 8707 D Non-qualified Stock Option 177.09 2030-03-15 Common Stock 8284 8284 D Each notional stock unit represents a right to receive one share of Gallagher common stock. The notional stock units become payable in July 2026 and following the reporting person's separation from service with Gallagher. Each share of phantom stock represents a right to receive one share of Gallagher common stock. These shares represent awards under the Age 62 Plan, a nonqualified deferred compensation plan of the Company, which have been deemed invested in Company common stock at the election of the reporting person. Participants vest in these awards when they attain age 62, or after a one-year period for participants who have attained age 61. One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. Grant date of 3/12/2020. Closing price of Gallagher common stock on February 28, 2025. One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. This report discloses the distribution of notional stock units (representing compensation previously deferred by the reporting person in the Arthur J. Gallagher & Co. Supplemental Savings and Thrift Plan) in the form of Gallagher common stock. The timing of this distribution in July 2026 is in accordance with the terms of the Supplemental Savings and Thrift Plan and the reporting person's election at the time of deferral. /s/ Monica Norzagaray, by power of attorney 2026-07-06