William Henry Donaldson (born June 2, 1931 in Buffalo, New York, USA) was the 27th Chairman of the U.S. Securities and Exchange Commission (SEC), serving from February 2003 to June 2005. He served as Under Secretary of State for International Security Affairs in the Nixon Administration, as a special adviser to Vice President Nelson Rockefeller, Chairman and CEO of the New York Stock Exchange, and Chairman, President and CEO of Aetna. Donaldson founded Donaldson, Lufkin & Jenrette. Donaldson attended both Yale University (B.A. 1953) and Harvard University (M.B.A. 1958). He was Chairman of the Carnegie Endowment for International Peace from 1999 to 2003. Donaldson returned to Yale and founded the Yale School of Management where he served as dean and professor of management studies. He also served in the United States Marine Corps.