Karen Lynch

Lynch, who oversees businesses that account for more than 95% of Aetna’s revenues, suffered a blow this year when a federal judge blocked the insurer’s acquisition of Humana—an integration the executive would have helped lead. Despite the companies’ decision to call off the merger, Aetna’s stock reached a record high this year. The share price was buoyed by the company’s decision to withdraw from all state Obamacare exchanges by next year, a move intended to reverse last year’s dip in profits.