James “Jim” Simons, a renowned mathematician who built a fortune on Wall Street and then became one of the nation’s biggest philanthropists, died May 10 at his home in Manhattan. He was 86.
The charitable foundation that Dr. Simons co-founded with his wife, Marilyn, announced the death but gave no specific cause.
Dr. Simons’s first career was in mathematics, making advances in the studies of particle physics such as quantum field theory and string theory. He led classes at the Massachusetts Institute of Technology and Harvard University before taking a job at the Institute for Defense Analyses in Princeton, N.J., as a code breaker for the National Security Agency. And from 1968 to 1978, he was chairman of the mathematics department at the State University of New York at Stony Brook.
In 1976, Dr. Simons received the American Mathematical Society’s Oswald Veblen Prize in Geometry for research that would prove to be influential to string theory and other areas of physics.
But in 1978, he traded academia for Wall Street. He leased a small office in a Long Island strip mall with the goal of using his skills in applied mathematics to guide investments in the stock market. The team he built was much like him: mathematicians, scientists and experts at prediction-based analysis using data and specialized computer coding.
The hedge fund he created, which eventually became known as Renaissance Technologies, pioneered the use of mathematical modeling — also known as quantitative trading — to pick stocks and other investments. The approach was wildly successful, helping Simons and his wife build over the years an estimated net worth of more than $30 billion.
“I wasn’t the fastest guy in the world,” Dr. Simons told the New York Times in 2014 about his problem-solving abilities in math. “I wouldn’t have done well in an Olympiad or a math contest. But I like to ponder. And pondering things, just sort of thinking about it and thinking about it, turns out to be a pretty good approach.”
James Harris Simons was born April 25, 1938, in Brookline, Mass. His father was the general manager of a shoe factory, and his mother was a homemaker. The family moved to nearby Newton while he was in high school.
As a boy, he was obsessed with logic and mathematical proofs, Dr. Simons recalled. One time his father was worried the car was close to running out of gas. Dr. Simons said he used theoretic math to explain to his incredulous father the impossibility of reaching zero.
“And I said to myself and then to him, ‘Well, you don’t have to run out of gas. You can use half of what you have, and then you can use half of that and then half of that, and you’ll never run out of gas,’” he recalled in a 2020 oral history with the American Institute of Physics.
His practical side, however, was not as sharp. During a school break over the holidays when he was 14, he was demoted to floor sweeper at a garden supply store. He was hired for a stockroom job but he repeatedly forgot where to put items.
He graduated from MIT with a mathematics degree in 1958 and received a doctorate in math from the University of California at Berkeley in 1961. His doctoral work explored the mathematical structures of curved spaces, which Albert Einstein had used in his general theory of relativity to explain how gravity bends space and time.
At the NSA, his political views eventually clashed publicly with those of his boss, Army Gen. Maxwell D. Taylor. In 1967, Taylor defended the Vietnam War in a New York Times Magazine article. Dr. Simons published a reply, saying the war undermined U.S. security and appealing for a military pullout “with the greatest possible dispatch.”
Soon after, he was dismissed. Stony Brook University on Long Island offered him the job as head of the math department.
In 1978, Dr. Simons started his investment firm. He retired as CEO of the hedge fund in 2010, then focused on philanthropic work through the foundation he and his wife founded in 1994 to support scientists and organizations engaged in research in science, math and education.
Over the years, the couple donated billions of dollars to hundreds of philanthropic causes. In 2023, they gave $500 million through their foundation to the State University of New York at Stony Brook to support the university’s endowment and boost scholarships, professorships, research and clinical care.
Dr. Simons came in second behind only Warren Buffett in the Chronicle of Philanthropy’s list of the biggest charitable donations from individuals or their foundations in 2023.
His marriage to Barbara Bluestein, a computer scientist, ended in divorce. He married Marilyn Hawrys, an economist, in 1977. One son from his first marriage, Paul Simons, was killed in a bicycle accident in 1996; a son from his second marriage, Nicholas Simons, drowned off Bali in Indonesia in 2003.
Besides his wife, survivors include two children from his first marriage; a daughter from his second marriage; five grandchildren and one great-grandson.
In the oral history interview, Dr. Simons was asked whether he saw a religious or moral underpinning to his philanthropy.
“It’s not a spiritual framework,” he replied. “It makes me feel good, to give away this money and see that it’s going to a good cause, and in particular with science, learning things.”
