A split appellate court in Pennsylvania has held that an insurer is estopped from asserting a policy exclusion that it failed to expressly raise in its reservation of rights letter. See Selective Way Ins. Co. v. MAK Servs., No. 1289 EDA 2019, 2020 Pa. Super. LEXIS 342 (Pa. Super. Ct. April 24, 2020). The court’s ruling is an important reminder that failure to properly reserve the insurer’s right to deny coverage can sometimes have significant consequences.