X0508 4 2024-02-07 0000315293 Aon plc AON 0001322803 Case Gregory C 200 EAST RANDOLPH ST. CHICAGO IL 60601 true true false false Chief Executive Officer false Class A Ordinary Stock 2024-02-07 4 G false 6052 0 D 306289 D Class A Ordinary Stock 2024-02-07 4 G false 6052 0 D 300237 D Class A Ordinary Stock 2024-02-07 4 G false 6052 0 A 128052 I By Trust Class A Ordinary Stock 2024-02-07 4 G false 6052 0 A 128052 I By Trust Class A Ordinary Stock 222985 I By GRAT Class A Ordinary Stock 145486 I By Trust Class A Ordinary Stock 145485 I By Trust Class A Ordinary Stock 400000 I By GRAT On December 19, 2023 the GRAT returned 177,015 shares to the reporting person as an annuity payment. On February 6, 2024, the reporting person contributed 400,000 shares previously held as direct to a new GRAT. /s/ Colby Alexis - Colby Alexis pursuant to a power of attorney from Greg Case 2024-02-09