Aon plc — Director's Dealing 2011

May 3, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AON CORP (AOC)
CIK: 0000315293
Period of Report: 2011-05-01

Reporting Person: FARMER JEREMY G O (Senior VP & Head of HR)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-05-01	Common Stock	M	1000	—	Acquired	68087	Direct
2011-05-01	Common Stock	F	415	$52.17	Disposed	67672	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-05-01	Restricted Stock Unit Award (Right to Receive)	$	M	1000	Disposed	2011-05-01	Common Stock (1000)	Direct

Footnotes

F1: Shares of common stock acquired upon the vesting of a restricted stock unit award.

F2: Shares of common stock withheld by the issuer for the payment of withholding taxes in connection with the vesting of a restricted stock unit award.

F3: The restricted stock unit award converts to shares of common stock on a 1-for-1 basis.

F4: Includes 924 shares held pursuant to the Aon employee stock purchase plan.