X0306 4 2012-08-01 0 0000315293 Aon plc AON 0001407939 Besio Gregory J C/O AON CORPORATE LAW DEPT 200 EAST RANDOLPH STREET, 8TH FL CHICAGO IL 60601 0 1 0 0 EVP/Chief HR Officer Class A Ordinary Shares 2012-08-01 4 M 0 10274 38.93 A 87680.43 D Class A Ordinary Shares 2012-08-01 4 S 0 10274 49.573 D 77406.43 D Class A Ordinary Shares 7739 I Through Aon Savings Plan and Supplemental Savings Plan Employee Share Option (Right to Buy) 38.93 2012-08-01 4 M 0 10274 D 2015-03-19 Class A Ordinary Shares 10274 0 D Includes 188.002 shares acquired pursuant to the Aon employee stock purchase plan and shares acquired pursuant to dividend reinvestment. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $49.55 to $49.63, inclusive. The reporting person undertakes to provide to Aon plc, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. Vesting of the options occurred in accordance with the terms of the Aon Stock Incentive Plan as follows: one-third of the options vested on each of the first through third anniversaries of the date of grant. The date of grant was March 19, 2009 Share option granted pursuant to the Aon Stock Incentive Plan. /s/ Matthew M. Rice - by Matthew M. Rice pursuant to a power of attorney from Gregory J. Besio 2012-08-03