That subrogation claim you have might be governed by ERISA, at least in some circuits…
Here’s the case of Thurber v. Aetna Life Insurance Company, __F.3d__ (2nd Cir. March 13, 2013) (Insurer’s counterclaim for return of overpaid benefits was an equitable claim for restitution, falling under ERISA’s jurisdiction).
FACTS. Sharon Thurber broke both legs