James Harris "Jim" Simons is an American hedge fund manager, mathematician, and philanthropist.
In 1982, Simons founded Renaissance Technologies, a private investment firm based in New York with over $15 billion under management. Simons retired at the end of 2009, as CEO, of what is one of the world's most successful hedge funds. Simons' net worth is estimated to be $10.6 billion.
Simons lives with his wife in Manhattan and Long Island, and is the father of three children; two of his children died young under tragic circumstances - a drowning and an auto accident.
Simons shuns the limelight and rarely gives interviews, citing Benjamin the Donkey in Animal Farm for explanation: "God gave me a tail to keep off the flies. But I'd rather have had no tail and no flies." On October 10, 2009, Simons announced he would retire on January 1, 2010 but remain at Renaissance as nonexecutive chairman.