Aspen Mails Revocation Materials to Shareholders

Recommends Rejecting Endurance's Coercive Legal Tactics That Serve to Facilitate an Ill-Conceived Offer Significantly Undervaluing Aspen Urges Shareholders to Sign, Date and Return BLUE Revocation Card to REJECT Endurance Proposals Aspen Insurance Holdings Limited (“Aspen”)

announced today that it is mailing its revocation materials--including a letter and a BLUE revocation card--to shareholders, in opposition to Endurance Specialty Holdings Ltd. (“Endurance”)

solicitation of authorizations. Aspen's Board of Directors urges shareholders to reject both of Endurance's proposals by promptly signing, dating and returning Aspen's BLUE revocation card and disregarding Endurance's white authorization card. Information on Aspen's response to Endurance's unsolicited offer, including links to press releases, presentations, and other important documents and SEC filings are available on the Internet at http://aspen.shareholderresource.com, or on Aspen's website at http://www.aspen.co.