14 people serve on the board of directors of four S&P 500 companies at the same time. Of those 14, four are women, according to BoardEx data. BoardEx is a business unit of TheStreet. American physicist Dr. Shirley Ann Jackson serves on the board of four publicly traded companies: FedEx ( FDX) , Public Service Enterprise Group ( PEG) , Medtronic (MDT) and International Business Machines (IBM) . Fellow FedEx director Susan Schwab also sits on four boards, including Caterpillar ( CAT) , Boeing ( BA) and Marriott International ( MAR) . Suzanne Nora Johnson serves on the board of directors at Pfizer ( PFE) , Visa (V) , American International Group (AIG) and Intuit ( INTU) . Former CEO of Lucent Technologies, Patricia Russo is a director for Merck ( MRK) , General Motors ( GM) , Arconic ( ARNC) and is the Chairman of the board for Hewlett Packard Enterprise ( HPE) .