Mutual mistake, ambiguity, and extrinsic evidence

The Fifth Circuit addressed the doctrine of mistake under Louisiana law in Fruge v. Amerisure, 663 F.3d 743 (2011).  After reminding that choice-of-law issues are waived unless presented to the district court, the Court considered reformation of an insurance policy under general contract principles.  The Court began by noting that Louisiana law allows reformation in the case of mutual mistake, and consideration of extrinsic evidence to prove such a mistake, even if the policy language is unambiguous.  It reviewed different post-accident reformation scenarios, noting that a Louisiana statute generally precludes a post-accident reformation to rescind coverage, and concluded that a reformation claim based on mutual mistake was cognizable in the post-accident setting presented in this case.  The Court reversed and remanded, noting that the extrinsic evidence could potentially prove that no mistake occurred.