William H. Donaldson, the Lion of Wall Street who led the SEC, dies at 93
William H. Donaldson, who made an early fortune as co-founder of the innovative securities firm Donaldson, Lufkin & Jenrette and later pushed for tougher financial regulation as chairman of the Securities and Exchange Commission in the wake of the Enron and WorldCom accounting scandals , died Wednesday at his home in Westchester County, New York, at the age of 93. The cause was leukemia, his son Adam said. Mr. Donaldson also briefly served as undersecretary of state under Henry A. Kissinger, ran the New York Stock Exchange and was chief executive of the insurance company Aetna Inc. In 1975, he…