Aspen Prices Public Offering of $150 million of Perpetual Non-Cumulative Preference Shares

Hamilton, Bermuda – 04 April, 2012 – Aspen Insurance Holdings Limited (“Aspen” or the “Company”; Ticker: NYSE:AHL; BSX: AHL.BH) has priced an underwritten public offering of 6,000,000 shares of 7.25% of Perpetual Non-Cumulative Preference Shares (the “Preference Shares”).

The Preference Shares have a liquidation preference of $25 per share (or $150,000,000 in aggregate liquidation preference). The underwriters have the option to purchase from Aspen up to an additional 900,000 Preference Shares (or $22,500,000 in aggregate liquidation preference).

The offering was made pursuant to an effective shelf registration statement and is expected to close on April 11, 2012, subject to customary closing conditions. Aspen intends to use the net proceeds from the offering for general corporate purposes, including supporting its insurance and reinsurance activities through its operating subsidiaries as well as repurchasing its outstanding ordinary shares as determined from time to time.

The Preference Shares rank equally with preference shares previously issued by Aspen, and have no fixed maturity date. Aspen may redeem all or a portion of the shares at a redemption price of $25 per share on or after July 1, 2017. Aspen intends to list the Preference Shares on the New York Stock Exchange under the symbol “AHLPRB”.

The offering was led by Citigroup Global Markets Inc., Barclays Capital Inc., UBS Securities LLC and Wells Fargo Securities, LLC as joint book-running managers.

This offering may be made only by means of a preliminary prospectus supplement and accompanying prospectus. Copies of the preliminary prospectus supplement and the final prospectus may be obtained, when available, from the U.S. Securities and Exchange Commission's website at www.sec.gov. Alternatively, these documents are available from the underwriters by contacting any of the following:

• Citigroup Global Markets Inc., Brooklyn Army Terminal, 140 58th Street, 8th Floor, Brooklyn, NY 11220, Attention: Prospectus Department, telephone (877) 858-5407 or email batprospectusdept@citi.com

• Barclays Capital Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717, telephone (888) 603-5847 or email Barclaysprospectus@broadridge.com

• UBS Securities LLC, 299 Park Avenue New York, NY 10171, Attention: Prospectus Specialist, telephone (877) 827-6444 ext. 561 3884

• Wells Fargo Securities, LLC, 1525 W W.T. Harris Boulevard, NC0675, Charlotte, NC 28262, Attention: Syndicate Operations, telephone (800) 326-5897 or email cmclientsupport@wellsfargo.com

About Aspen Insurance Holdings Limited (“Aspen”)

Aspen provides reinsurance and insurance coverage to clients in various domestic and global markets through wholly-owned subsidiaries and offices in Bermuda, France, Germany, Ireland, Singapore, Switzerland, the United Kingdom and the United States. For the year ended December 31, 2011, Aspen reported $9.5 billion in total assets, $4.5 billion in gross reserves, $3.2 billion in shareholders’ equity and $2.2 billion in gross written premiums. Its operating subsidiaries have been assigned a rating of “A” (“Strong”) by Standard & Poor’s, an “A” (“Excellent”) by A.M. Best and an “A2” (“Good”) by Moody’s Investors Service.

For further information

Please visit www.aspen.bm or contact:

Investors

Kerry Calaiaro, Senior Vice President, Investor Relations, Aspen

Kerry.Calaiaro@aspen.co                  +1 646 502 1076

Media

Tim Dickenson, Global Head of Communications, Aspen

Tim.Dickenson@aspen.co                 +44 20 7184 8034

Europe and Asia – Citigate Dewe Rogerson

Justin Griffiths

Justin.Griffiths@citigatedr.co.uk        +44 20 7638 9571

North America – Abernathy MacGregor

Allyson Vento

amv@abmac.com                              +1 212 371 5999