Tri-Star Theme Builders, Inc. v. Onebeacon Insurance Company

MEMORANDUM

This is an appeal from a judgment entered in the United States District Court for the District of Arizona in favor of OneBeacon Insurance Company (“OneBeacon”). The underlying complaint, which was filed by Tri-Star Theme Builders, Inc. /PCL Construction Services, Inc. (“TriStar”), alleged that OneBeacon failed to defend and indemnify Tri-Star in an action against it by the Colorado River Indian Tribes (“Tribes”). Tri-Star, the general contractor on a resort and casino project (“Project”) being developed by the Tribes, had subcontracted the plumbing and HVAC work to Golden West Mechanical (“Golden West”). Pursuant to the subcontract agreement, Golden West agreed to make Tri-Star an additional insured under its commercial general liability (“CGL”) insurance policy. The first policy was entered into on March 24, 1998, three days before Golden West’s subcontract agreement was formally executed.

Subsequently, Golden West proceeded to obtain a rider to its CGL policy, effective April 20,1998, which provided that the “Who Is An Insured” section of the policy (Section II) is amended to include “[TriStar], but only with respect to liability arising out of ... [Golden West’s]…