James Harris Simons (April 25, 1938 – May 10, 2024) was an American hedge fund manager, investor, mathematician, and philanthropist.

[12] In 2016, the International Astronomical Union named asteroid 6618 Jimsimons, which Clyde Tombaugh discovered in 1936, after Simons in honor of his contributions to mathematics and philanthropy.

His 1962 Berkeley PhD thesis, written under the direction of Bertram Kostant, gave a new proof of Berger's classification of the holonomy groups of Riemannian manifolds.

Later, mathematical physicist Albert Schwarz discovered early topological quantum field theory, which is an application of the Chern–Simons form.

Simons also tried starting a trading company named iStar with colleagues including Richard Leibler, but was discovered by management and the effort failed.

[23] After being forced to leave the IDA due to his public opposition to the Vietnam War, he joined the faculty at Stony Brook University.

[24] Simons was asked by IBM in 1973 to attack the block cipher Lucifer, an early but direct precursor to the Data Encryption Standard (DES).

[25] Simons founded Math for America, a nonprofit organization, in January 2004 with a mission to improve mathematics education in United States public schools by recruiting more highly qualified teachers.

[26] Simons founded a hedge fund management firm called Monemetrics, which he later renamed to Renaissance Technologies.

[29][30][31] Medallion, the main fund which is closed to outside investors, has earned over $100 billion in trading profits since its inception in 1988.

[32] Renaissance employs specialists with non-financial backgrounds, including mathematicians, physicists, signal processing experts and statisticians.

[40] In 2014, Simons reportedly earned US$1.2 billion, including a share of his firm's management and performance fees, cash compensation and stock and option awards.

[45] At the time of his death, Simons' net worth was estimated to be $31.4 billion, making him the 55th-richest person on Forbes' 2024 The World's Billionaires list.

[58] According to The Wall Street Journal in May 2009, Simons was questioned by investors on the dramatic performance gap of Renaissance Technologies' portfolios.

"Renaissance Technologies was able to avoid paying more than $6 billion in taxes by disguising its day-to-day stock trades as long term investments", said Sen. John McCain (R., Ariz.), the committee's ranking Republican, in his opening statement.

"[61] In September 2021, it was announced that Simons and his colleagues would pay billions of dollars in back taxes, interest and penalties to resolve the dispute, one of the biggest in IRS history.

The couple and their foundation have funded the renovation of the building housing the mathematics department, which in 2016 was named in their honor, and endowed the Simons Center for the Social Brain.

[69][70] In 2020, the foundation made separate grants to Berkeley totaling over $46 million to increase the institute's endowment and support its operations.

[74][75][76] The Simons Foundation established the Flatiron Institute in 2016,[77] to house five groups of computational scientists (each with 60 or more PhD level researchers).

[84] In 2011, the couple broke that record again with a $150 million donation to Stony Brook, which went to research in medical sciences, the construction of a life sciences building, the creation of a neurosciences institute and a center for biological imaging, the study of cancer and infectious diseases, 35 new endowed professorships and 40 fellowships for graduate students.

In order to secure the donation, Stony Brook was allowed to raise its annual tuition in opposition to traditional New York state policy.