For 2017, 91 percent of the insurer's MA members will be in four-star or higher Medicare Advantage and prescription drug (MA-PD) plans, it said, noting that it has the highest percentage of Medicare members enrolled in four-star plans among publicly traded companies. Cigna also saw a reduction in its ratings, as next year about 20 percent of its MA customers will be in plans with four stars or higher, the insurer said in a Securities & Exchange Commission filing. Like Humana, it said the ratings dip is attributable to a CMS audit; in January, the agency banned Cigna from selling new Medicare products due to " substantial failures " to correct compliance violations.