Aon plc — Director's Dealing 2011

Mar 1, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AON CORP (AOC)
CIK: 0000315293
Period of Report: 2011-02-25

Reporting Person: LIEB PETER M (EVP & General Counsel)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-02-25	Common Stock	M	1708	—	Acquired	1820.443	Direct
2011-02-25	Common Stock	F	538	$52.49	Disposed	1282.443	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-02-25	Restricted Stock Unit Award (Right to Receive)	$	M	1708	Disposed	2011-02-25	Common Stock (1708)	Direct
2011-02-28	Phantom Stock	$	A	610.01	Acquired		Common Stock (610.01)	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: Each share of phantom stock acquired under the issuer's deferred compensation plan represents the right to receive one share of Aon common stock or the cash value thereof.

F5: Shares of phantom stock are payable in cash in ten annual installments following the reporting person's retirement. Subject to the issuer's compliance procedures for its Section 16 reporting officers, the reporting person may transfer shares of common stock into an alternative investment account under the issuer's deferred compensation plan.

F6: Includes shares acquired pursuant to dividend reinvestment.

F7: This amount represents phantom shares acquired in connection with the deferral of a portion of the reporting person's short-term incentive for 2010 performance and a deferral of a portion of the reporting person's base salary.

F8: Includes 112.443 shares held pursuant to the Aon employee stock purchase plan.