Aspen Insurance Holdings Announces Initial Loss Estimates - Australia, New Zealand And Comments on Japan

Hamilton, Bermuda – 15 March, 2011 — Aspen Insurance Holdings Limited (the “Company”; NYSE:AHL) today announced an estimate of losses from the 2011 Australian Floods and Cyclone Yasi (the "2011 Australian Catastrophe Events"), and the New Zealand Earthquake of February 21, 2011 (the "February 2011 New Zealand Earthquake") and commented on the Tohoku Earthquake.

The Company's initial estimate of losses from the 2011 Australian Brisbane Floods which took place between January 10 and 17, 2011, is in the region of US$30 million post tax and net of reinstatement premiums. The Company believes that its losses in respect of Cyclone Yasi, the Victoria Floods, which took place between January 13 and 17, 2011, and the other Queensland floods are not material.

The Company's initial estimate of losses from the February 2011 New Zealand Earthquake is in the region of US$60 million post tax and net of reinstatement premiums and applicable reinsurance, in respect of which the Company has a fully collateralized retrocession cover of US$50 million excess of US$50 million. This initial loss estimate for the February 2011 New Zealand Earthquake is consistent with an industry loss of US$12 billion. The Company has assumed a total loss to all domestic New Zealand placements for this event which is similar to the Company's approach adopted on estimated losses from the September 2010 New Zealand earthquake.

The Company's post tax loss estimate for the September 2010 New Zealand earthquake remains US$47 million, net of reinstatement premiums. The Company did not have any retrocession in force for the September 2010 New Zealand earthquake.

The Company's estimates are based on its review of individual treaties and policies expected to be impacted and client data received to date and have taken into account current total insured market loss estimates, both from published sources and the Company's internal analysis. In view of the uncertainties associated with these initial estimates, actual losses may differ materially from these preliminary estimates.

The tragic loss of life and extent of devastation continues to unfold following the earthquake and tsunami that struck the North Eastern Coast of Japan on March 11, 2011 ("the Tohoku Earthquake"). The Company has initiated its estimation process in connection with expected claims relating to this event but believes it is too early to issue a loss estimate at this time. However, the Company does not have any known exposure to property damage, business interruption or liability for any nuclear incidents arising from the Tohoku Earthquake.

About Aspen Insurance Holdings Limited

The Company 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 twelve months ended December 31, 2010, The Company reported gross written premiums of $2,076.8 million, net income of $312.7 million and total assets of $8.8 billion. Its operating subsidiaries have been assigned a financial strength rating of "A" ("Strong") by Standard & Poor's, an "A" ("Excellent") by A.M. Best and an "A2" ("Good") by Moody's Investors Service.

Investor Contact:

Aspen Insurance Holdings Limited

Kerry Calaiaro, Senior Vice President, Investor Relations    

+1 646-502-1076
Kerry.Calaiaro@aspen.bm

Noah Fields, Vice President Investor Relations                    

+1 441-297-9382

Noah.Fields@aspen.bm

European Press Contact:

Citigate Dewe Rogerson

Justin Griffiths/Sarah Gestetner                                

T: +44 (0) 20 7282 2920

North American Press Contact:

Abernathy MacGregor

Carina Davidson/Allyson Morris                                

T: +1 212-371-5999