Issuer:

Aon plc

Securities:

4.45% Senior Notes due 2043

Guarantor

Aon Corporation

Legal Format:

SEC Registered

Amount:

$250,000,000

Ranking:

Senior Unsecured

Expected Ratings(1):

Moody’s Investors Service: Baa2 (positive)
Standard & Poor’s: BBB+ (stable)
Fitch: BBB+ (stable)

Trade Date:

May 21, 2013

Settlement Date (T+3):

May 24, 2013

Maturity Date:

May 24, 2043

Reference Treasury:

3.125% due February 15, 2043

Reference Treasury Yield and Price:

3.115% or 100-06

Reoffer Spread to Treasury:

+137.5 bps

Reoffer Yield:

4.490%

Coupon:

4.45%

Denominations:

$2,000 and multiples of $1,000

Interest Payment Dates:

Semi-annually in arrears on May 24 and November 24, beginning on November 24, 2013

Price to Public:

99.344%

Proceeds to Issuer (before expenses):

$246,172,500

CUSIP / ISIN:

00185AAC8 / US00185AAC80

Optional Redemption:

We may redeem all of the Notes at any time or some of the Notes from time to time at a redemption price equal to the greater of 100% of the principal amount of the Notes and a make whole using a discount rate of Treasury plus 20 basis points.

On or after February 24, 2043, we may redeem any or all of the Notes at a redemption price equal to 100% of the principal amount of the Notes

In the event of certain changes in respect of taxes applicable to the Notes or the Guarantee, we may redeem the Notes in whole at any time at a redemption price equal to 100% of the principal amount of the Notes.

See “Description of the Securities—Optional Redemption” and “Description of the Securities—Optional Tax Redemption” in the preliminary prospectus supplement for more information.

Joint Book-Running Managers:

Morgan Stanley & Co. LLC and Goldman, Sachs & Co.

Co-Managers:

Aon Benfield Securities, Inc., Barclays Capital Inc., Deutsche Bank Securities Inc., J.P. Morgan Securities LLC, Loop Capital Markets LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated, The Williams Capital Group, L.P. and UBS Securities LLC.

Conflicts:

Aon Benfield Securities, Inc. is an indirect wholly owned subsidiary of Aon plc. This offering is subject to, and will be conducted in compliance with, the requirements of Rule 5121 of the Financial Institution Regulatory Authority (“FINRA”) regarding a FINRA member firm distributing the securities of an affiliate.

Certain of the underwriters or their affiliates may hold our commercial paper and, accordingly, may receive proceeds from this offering. To the extent that any one underwriter, together with its affiliates, receives more than 5% of the net proceeds, such underwriter would be deemed to have a “conflict of interest” with us in regard to this offering under FINRA Rule 5121. Accordingly, this offering will be made in compliance with the applicable provisions of FINRA Rule 5121.