In Evanston Ins. Co. v. ATOFINA Petrochem. Inc., 2008 WL 400394, (Tex. 2008), the Supreme Court of Texas held that excess insurance policies provide coverage for liabilities arising from an additional insured's sole negligence, and that in cases where an insurance company wrongfully denies coverage to an additional insured policyholder the insurer is barred from challenging a settlement when its insured agrees to settle with a plaintiff.

The trial court granted summary judgment to Evanston , but the intermediate court of appeals reversed in favor of Atofina. The Texas Supreme Court initially held that while Atofina was an insured, coverage depended on whether Atofina was solely negligent. The Court later granted Atofina's Motion for Rehearing, vacated its earlier opinion, and rendered judgment for Atofina for the full amount of the settlement.