Alterra Capital Holdings Limited ("Alterra") (NASDAQ: ALTE; BSX: ALTE.BH) today announced that its subsidiary, Alterra America Insurance Company ("Alterra America"), has entered into a long-term partnership with Ullico Casualty Group, Inc. ("UCG"), a subsidiary of Ullico Inc. ("Ullico"), that will allow Alterra to effectively participate in the US multiemployer and governmental fiduciary liability and union liability insurance market.

Doug Worman, Executive Vice President of Alterra and Chief Executive Officer of Alterra US Insurance, said: "We are pleased to have reached an agreement with Ullico Casualty Group. We believe our new partnership will benefit from the particular strengths of both companies, and will provide Alterra with a meaningful production source for profitable union program business."

UCG will offer new and renewal professional fiduciary and union liability insurance policies from Alterra America beginning January 1, 2013. UCG claims professionals and underwriters will work with its producers to ensure a seamless transition to Alterra America. In 2011, UCG wrote gross premiums of approximately $50 million related to the business that is the subject of this partnership.

For over 25 years, Ullico has provided a comprehensive portfolio of property and casualty insurance products designed to protect and grow the labor movement. Ullico Casualty Group, Inc. is a member of the Ullico family of companies, which includes The Union Labor Life Insurance Company; Ullico Casualty Company; Ullico Investment Company, Inc.; and Ullico Investment Advisors, Inc.

About Alterra Capital Holdings Limited

Alterra Capital Holdings Limited is a global enterprise dedicated to providing diversified specialty insurance and reinsurance products to corporations, public entities, and property and casualty insurers.

Cautionary Note Regarding Forward-Looking Statements

This release includes forward-looking statements that reflect Alterra's current views with respect to future events and financial performance. In particular, statements regarding future rate movements are forward looking statements. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those suggested by such statements. For further information regarding cautionary statements and factors affecting Alterra's future results, please refer to the most recent reports on Form 10-K and Form 10-Q and other documents filed by Alterra with the SEC. Alterra undertakes no obligation to update or revise publicly any forward-looking statement whether as a result of new information, future developments or otherwise.

Alterra Capital Holdings Limited
Susan Spivak Bernstein, 1-212-898-6640
Senior Vice President
susan.spivak@alterra-bm.com
or
Kekst and Company
Peter Hill, 1-212-521-4800
peter-hill@kekst.com