X0306 4 2019-02-20 0 0000315293 Aon plc AON 0001506411 O'Connor Michael J 200 EAST RANDOLPH ST. CHICAGO IL 0 1 0 0 Co-President Class A Ordinary Stock 2019-02-20 4 S 0 12068 172.51 D 134531.091 D Class A Ordinary Stock 2019-02-20 4 S 0 10747 172.99 D 123784.091 D The transactions reported were effected pursuant to a trading plan meeting the requirements of SEC Rule 10b5-1 entered into on November 8, 2018 The price reported is a weighted average price. Shares were sold in a series of transactions within the same trading day at prices ranging from $171.79 to $172.78, inclusive. Full information regarding the number of shares sold at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. The price reported is a weighted average price. Shares were sold in a series of transactions within the same trading day at prices ranging from $172.79 to $173.25, inclusive. Full information regarding the number of shares sold at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer /s/ Molly Johnson- Molly Johnson pursunat to power of attorney from Michael O'Connor 2019-02-26