Jim Simons, the billionaire investor, mathematician and philanthropist, died on Friday in New York City, according to his foundation, the Simons Foundation. Simons was 86 years old.

Using advanced computers, he went from M.I.T. professor to multibillionaire. His Medallion fund had 66 percent average annual returns for decades.

Billionaire investor James Simons, the mathematician and Cold War code-breaker who founded one of the world's most prominent and profitable hedge funds, Renaissance Technologies, has died at 86, his foundation said on Friday.