Sandra L. Helton

Ms. Helton has served as a director of the company since February 2018. Ms. Helton serves on the Board of Directors of Principal Financial Group (Principal), a global diversified financial institution, where she chairs the Audit Committee and serves on Principal’s Executive Committee and Finance Committee, which she previously chaired. Ms. Helton also serves on the Board of Directors of Covetrus, a worldwide animal health business, chairs their Audit Committee and serves on the Nominating and Governance Committee. Prior to the acquisition of Lexmark International Inc. in November 2016, she served on their Board of Directors and Finance and Audit Committee. Ms. Helton also served on the board of Covance Inc., a leading global drug development services company, prior to LabCorp acquiring the company in 2015. She chaired the Finance and Audit Committee and served on the Nominating and Governance Committee of Covance. Ms. Helton was Executive Vice President and Chief Financial Officer, and member of the Board of Directors of Telephone and Data Systems, Inc. (TDS) from 1998 through 2006. Her responsibilities included strategic planning, finance, and information systems, among other functions. Ms. Helton also served on the Boards of United States Cellular Corporation and Aerial Corporation, TDS’s publicly traded subsidiaries. Before TDS, Ms. Helton was Vice President, Corporate Controller of Compaq Computer Corporation. Prior to Compaq, Ms. Helton held over a dozen increasingly responsible positions during her 26-year tenure with Corning Incorporated. Ms. Helton serves on the Board of Northwestern Memorial Foundation. She previously served on the Board of Northwestern Memorial Health Care, a nationally recognized academic medical center, where she chaired the Audit Committee and was a member of the Executive, Finance, and Investment Committees. Ms. Helton holds an S.M. in Finance from Massachusetts Institute of Technology’s Sloan School of Management and graduated with a B.S. in Mathematics from the University of Kentucky.