Investment firm Altamont Capital Partners has agreed to acquire Topa Insurance Group, a Calabasas-based subsidiary of Topa Equities in Los Angeles, the companies announced Wednesday.

Altamont, based in the Bay Area, will take majority control of the business, but Topa Equities will retain a minority equity stake after the deal closes. Financial terms of the transaction were not disclosed.

Topa Insurance specializes in property and casualty insurance, a strategy that will not change under Altamont’s management.

“We are strong proponents of the specialty P&C insurance business and believe that Topa has built a phenomenal platform in the space,” said Altamont Principal Sam Gaynor in a statement. “Topa will serve as our foundational specialty P&C insurance carrier business in the U.S. and we believe our expertise in the space will drive numerous opportunities for growth over the coming years.”

Topa Equities Chairman William Anderson added: “Our family and board of directors were most interested in finding the right long-term partner who will continue to grow the business. We believe that Altamont will be an excellent steward of Topa Insurance.”

Founded by John E. Anderson in 1956, Topa Equities Ltd. is a private, family-owned, diversified holding company. Headquartered in Los Angeles, the company owns more than 25 subsidiaries with primary locations in Southern California, Hawaii and the U.S. Virgin Islands.

Topa Equities was represented by Drinker Biddle & Reath LLP in Philadelphia and Dowling Hales in New York. Altamont was represented by Sidley Austin LLP in Chicago and RBC Capital Markets in Toronto.