Houston’s HCC Insurance Holdings said Pioneer General Insurance Co. will merge into American Contractors Indemnity Co., both of which are wholly owned subsidiaries of HCC.

HCC Insurance Holdings is opening new Primary Casualty and Excess Casualty divisions, which company officials say should serve to extend its underwriting activities.

HCC Insurance Holdings said that its subsidiary, Perico Life Insurance Co., combined its operations with HCC Life Insurance Co.

Risk and reinsurance specialist Guy Carpenter & Co. announced an agreement to buy all the shares of United Kingdom-based reinsurance broker Rattner Mackenzie Limited from HCC Insurance Holdings Inc.