Mark T. Bertolini (born 1956) is an American businessman who is the Co-CEO of Bridgewater Associates, one of the world's largest hedge funds. He was previously the CEO of Aetna, a Fortune 50 diversified health care benefits company with over $60 billion in 2015 revenue. Bertolini assumed the role of CEO on November 29, 2010 and of Chairman on April 8, 2011 until Aetna was sold to CVS on November 28, 2018.