A federal court in Oklahoma granted summary judgment to an insurer, finding that the “other insurance” provision in its policies could be enforced to prevent stacking of limits for the insured’s tractor and trailer, each covered under separate policies issued by the same insurer. Shelter General Ins. Co. v. EarthSmart Const. Inc., 2015 WL 6672216 (N.D. Okla. Nov. 2, 2015).

The insurer issued two policies to an insured, one covering a tractor and the other a trailer, both owned by the insured. The insured was involved in an accident where the tractor/trailer rig caused two vehicles to run off the road, collide and catch fire. The insurer sought a declaration that stacking of the policy limits was improper as the policies were separate, each containing its own “other insurance” provisions providing: “If this coverage form and any other coverage form or policy issued to you by us … apply to the same ‘accident’, the aggregate maximum Limit of Insurance under all the coverage forms or policies shall not exceed the highest applicable Limit of Insurance under any one coverage form or policy.” The court found, under Oklahoma law, that “other insurance” provisions are enforceable against third parties seeking liability coverage. It further held that the payment of separate premiums was not relevant to enforcement of “other insurance” provisions against third parties and that stacking of the policies at issue might occur if there were a fact issue as to what damage was caused by the tractor versus the trailer, but that since it was clear that that was not the case, stacking was not permissible.