Fred Hassan is a Partner and Managing Director at Warburg Pincus, a private partnership focused solely on private equity. Prior to this, he served as Chairman and Chief Executive Officer of Schering-Plough Corporation until its merger with Merck & Co. Hassan also worked at Wyeth, with responsibility for its pharmaceutical and medical products business. In 2014, a CNBC panel named him to a list of those who have had the most profound impact on the world of business in the previous quarter-century.