Aon plc — Director's Dealing 2010

Mar 1, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AON CORP (AOC)
CIK: 0000315293
Period of Report: 2010-02-25

Reporting Person: Besio Gregory J (EVP/CAO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-02-25	Common Stock	A	34372	—	Acquired	38767	Direct
2010-02-25	Common Stock	F	11438	$40.99	Disposed	27329	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-02-25	Restricted Stock Unit Award (Right to Receive)	$	A	6831	Acquired	2013-02-25	Common Stock (6831)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	4585	Indirect

Footnotes

F1: Represents shares of common stock issued upon the settlement of performance share units originally granted under the second cycle of the Leadership Performance Program ("LPP2"). The number of shares issued was determined by the Organization and Compensation Committee of Aon's Board of Directors on February 25, 2010 based upon Aon's performance relative to a cumulative adjusted three year earnings per share target for the period beginning January 1, 2007 and ending December 31, 2009. In accordance with the terms of LPP2, and the achievement of specified growth targets under LPP2, settlement occurred at 200% of the original target value. The terms of LPP2 are more fully described in a Current Report on Form 8-K filed with the SEC on March 21, 2007, and in the plan document filed as Exhibit 10.2 to Aon's Quarterly Report on Form 10-Q for the quarter ended March 31, 2008 filed with the SEC on May 9, 2008.

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

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

F4: The restricted stock unit award will vest in accordance with the terms of the Aon Stock Incentive Plan as follows: 33 1/3% of the awards will vest on each of the first through third anniversaries of the date of grant.

F5: Includes 378 shares held through the Aon employee stock purchase plan.