Aon Corporation Stock Ownership Guidelines for Nonmanagement Directors

Purpose:  The purpose of the Stock Ownership Guidelines for Nonmanagement Directors is to align the interests of nonmanagement directors with the long-term interests of holders and further promote the commitment of Aon plc (“Aon”) to sound corporate governance.

Ownership Requirement:  Each nonmanagement director is currently expected to hold an investment position in Aon common stock equal in value to three times the annual retainer paid to directors. Effective January 1, 2011, each nonmanagement director will be expected to hold an investment position in Aon common stock equal in value to five times the annual retainer.

Measurement:  Compliance with these ownership guidelines will be measured on the first trading day of each calendar year, using the annual director retainer then in effect, and the closing price of Aon common stock on that day.

Transition Period:  There will be a transition period of five years for nonmanagement directors to achieve the ownership requirement; however, notwithstanding the foregoing, each new nonmanagement director is expected to hold 1,000 shares within the first year of joining the Board or transitioning from a management director to a nonmanagement director. If at any time the annual retainer increases, the nonmanagement director will have five years from the time of such increase to acquire any additional shares needed to meet these guidelines. Nonmanagement directors will be expected to make steady progress toward meeting the guidelines throughout the five-year transition period.

Holdings Considered:  The following holdings will be considered when measuring stock ownership:

• Shares owned individually, shares owned jointly with a spouse, or shares owned separately by a spouse and/or children that share the director's household;
• Share equivalents held in accounts under the Aon plc Outside Director Stock Award and Retirement Plan or the Aon plcOutside Director Deferred Compensation Plan; and
• Vested deferred stock units held under the Aon plc Non-Employee Directors' Deferred Stock Unit Plan.

Effective Date of Policy: July 21, 2006 (as revised July 18, 2008 and further revised September 16, 2010).