Aetna was named as a respondent in the arbitration proceeding Oct. 28. The proceeding was the result of a lawsuit the hospitals filed in Florida court Aug. 25, 2015. The HCA-owned hospitals' arbitration proceeding concerned Aetna's out-of-network and administration practices in Florida for its individual ACA exchange products from 2014-16. Aetna largely exited the individual exchange business at the end of 2016. The arbitrator awarded the claimant hospitals roughly $150 million Oct. 15. In its SEC filing, submitted Oct. 30 with Aetna's third quarter earnings, the health insurer said it intends "to continue to defend ourselves vigorously against the claimant hospitals' claims and to appeal the arbitrator's decision." More articles on legal & regulatory issues: 9 latest healthcare industry lawsuits, settlements Judge halts Maine hospital merger Aetna's $50M overbilling case against medical group moves forward