American computer scientist and businessman
Robert Mercer
Robert Leroy Mercer is an American hedge fund manager, computer scientist, and political donor.
By globalcelebwiki Editorial Desk, adapted from Wikipedia · Published 29 September 2026
- Profession
- American computer scientist and businessman
- Born
- 11 July 1946
- Birthplace
- Santa Clara
- Nationality
- American

Overview
Robert Leroy Mercer (born July 11, 1946) is an American hedge fund manager, computer scientist, and political donor. Mercer was an early artificial intelligence researcher and developer and is the former co-CEO of the hedge fund company Renaissance Technologies.
Mercer played a controversial role in the campaign for the United Kingdom to leave the European Union, led by Dominic Cummings, with £3.9 million being spent on his data analytics and machine learning company AggregateIQ. He has also been a major funder of organizations supporting right-wing political causes in the United States, such as Breitbart News, the now-defunct Cambridge Analytica, and Donald Trump's 2016 campaign for president. He is the principal benefactor of the Make America Number 1 super PAC.
In November 2017, Mercer announced he would step down from Renaissance Technologies and sell his stake in Breitbart News to his daughters. He was the majority owner of SCL Group, a self-described "global elections management agency", before it was dissolved in 2018. In 2021, Mercer was involved in possibly the largest tax settlement in U.S. history, as he, James Simons, and other executives at the hedge fund Renaissance Technologies were ordered to pay as much as $7 billion to the IRS in back taxes.
Early life and education
Mercer grew up in New Mexico. He developed an early interest in computers and in 1964 attended a National Youth Science Camp in West Virginia where he learned to program a donated IBM computer. He went on to get a bachelor's degree in physics and mathematics from the University of New Mexico. While working on his degree, he had a job at the Air Force Weapons Laboratory at Kirtland Air Force Base writing programs where, though he felt he produced good work, he felt it was not optimized. He later said the experience left him with a "jaundiced view" of government-funded research. He earned a Ph.D. in computer science from the University of Illinois at Urbana–Champaign in 1972.
Career
Mercer joined IBM Research in the fall of 1972 and worked at the Thomas J. Watson Research Center in Yorktown, New York, where he helped develop Brown clustering, a statistical machine translation technique, as part of a speech recognition and translation research program led by Frederick Jelinek and Lalit Bahl. He also worked on IBM alignment models. In June 2014, Mercer received the Association for Computational Linguistics Lifetime Achievement Award for this work.
In 1993, Mercer joined hedge fund Renaissance Technologies after being recruited by executive Nick Patterson. The founder of Renaissance, James Harris Simons, a mathematician, preferred to hire mathematicians, computer scientists, and physicists rather than business school students or financial analysts. Mercer and a former colleague from IBM, Peter Brown, became co-CEOs of Renaissance when Simons retired in 2009. Renaissance's main fund, Medallion, earned 39% per year on average from 1989 to 2006.
In 2014, a bipartisan Senate panel estimated that Medallion investors underpaid their taxes by some $6.8 billion over more than a decade, by masking short-term gains as long-term returns. In 2014, Renaissance managed $25 billion in assets. In November 2017, Mercer announced that he would be stepping down from his position at Renaissance Technologies. The decision was taken after the hedge fund faced a backlash over Mercer's political activism.
Mercer appears in the Paradise Papers as a director of eight Bermuda companies, some of which appear to have been used to legally avoid US taxes.
Political activities and views
In 2015, The Washington Post called Mercer one of the ten most influential billionaires in politics. Since 2006, Mercer has donated about $34.9 million to Republican political campaigns in the US.
Mercer has given $750,000 to the Club for Growth, $2 million to American Crossroads, and $2.5 million to Freedom Partners Action Fund. In 2010, he financially supported fringe biochemist Art Robinson's unsuccessful efforts to unseat Peter DeFazio in Oregon's 4th congressional district. In the 2013-2014 election cycle, Mercer donated the fourth largest amount of money among individual donors and the second most among Republican donors.
Mercer joined the Koch brothers’ conservative political donor network after the 2010 Citizens United v. FEC, but Mercer and his daughter, Rebekah Mercer, decided to establish their own political foundation. The Mercer Family Foundation, run by Rebekah, has donated to a variety of conservative causes.
Mercer has donated to The Heritage Foundation, the Cato Institute, the Media Research Center, Reclaim New York, GAI, and Citizens for Self-Governance. In 2013, Mercer was shown data by former Jimmy Carter pollster Patrick Caddell, who has been critical of top Democrats, and commissioned more research from Caddell that showed "voters were becoming alienated from both political parties and mainstream candidates".
Mercer was the main financial backer of the Jackson Hole Summit, a "shadow" conference (not to be confused with a similarly named Federal Reserve conference) that took place in Wyoming in August 2015 to advocate for the gold standard. He has also supported Doctors for Disaster Preparedness, Fred Kelly Grant (an Idaho activist who encourages legal challenges to environmental laws), a campaign for the death penalty in Nebraska, and funded ads in New York critical of the so-called "ground-zero mosque".
In popular culture
Mercer was portrayed by actor Aden Gillett in the 2019 HBO and Channel 4 produced drama entitled Brexit: The Uncivil War.
Personal life
Mercer and his wife Diana Lynne Dean have three daughters: Jennifer ("Jenji"), Rebekah ("Bekah"), and Heather Sue. Rebekah runs the Mercer Family Foundation. The three Mercer daughters formerly owned a bakery called Ruby et Violette.
Mercer plays competitive poker and owns an HO scale model railroad. In 2009, Mercer filed suit against RailDreams Custom Model Railroad Design, alleging that RailDreams overcharged him by $2 million.
Sources and references
Spotted something wrong? Report a correction.
Related profiles
43rd President of the United States
George W. Bush
George Walker Bush is an American former politician, businessman, and Air Force veteran who served as the 43rd president of the United States from 2001 to 2009.
Read biography ↗American inventor and businessman
Thomas Edison
Thomas Alva Edison was an American inventor and businessman known for his work on the incandescent light bulb, the phonograph, electric power distribution and early motion pictures.
Read biography ↗