Gates vs Peterffy

Microsoft and Interactive Brokers.

The differences

Forbes puts Bill Gates about $10.8B ahead of Thomas Peterffy.Forbes figures from 15 Oct 2026 and 5 Sep 2026.
Both started the company their money comes from.
Thomas Peterffy is about 11 years older than Bill Gates.
Bill Gates has signed the Giving Pledge; Thomas Peterffy has not.

Put someone else on either side

Gates

Peterffy

Net worth, Forbes: $118BForbes, 15 Oct 2026; $107BForbes, 5 Sep 2026
Net worth, Bloomberg: $119BBloomberg, 16 Oct 2026; $104BBloomberg, 11 Oct 2026
Forbes rank: No. 17Real-Time list, 15 Oct 2026; No. 20Real-Time list, 5 Sep 2026
Billionaire since: 1987Forbes first listed him as a billionaire in 1987; Not stated

How it started: Co-founded itCo-founded Microsoft with Paul Allen in 1975; Founded itFormed the business now known as Interactive Brokers in 1977 after buying an American Stock Exchange seat
Main source: Cascade Investment, built from Microsoft stock sales and dividendsBloomberg: 'The majority of Bill Gates' fortune is derived from Cascade Investment'; Interactive Brokers stock, held through IBG HoldingsBloomberg: 'The majority of Thomas Peterffy's fortune is derived from Interactive Brokers Group'
Companies: MicrosoftMicrosoft: Co-founder; technology advisor to the CEO; Interactive BrokersInteractive Brokers: Founder and chairman
Biggest stake: Microsoft1% owned; Interactive Brokers67.5% owned

Born: 28 Oct 1955Seattle, Washington, United States; 1944Budapest, Hungary
Country: United StatesLives in Medina, Washington, United States; United StatesLives in Palm Beach, Florida, United States
Education: Left university without a degreeHarvard University, left without a degree (honorary degree in 2007); Left university without a degreeAttended the College of Surveying in Hungary; studied at New York University without finishing
Parents: Father William H. Gates Sr. was an attorney and civic leader; mother Mary Gates was a schoolteacher, University of Washington regent and chair of United Way International; Descended from Hungarian aristocrats who lost nearly everything under Soviet rule; arrived in the US in 1965 at 21 with no moneyForbes profile; parents' occupations not stated

Giving Pledge: Signed in 2010Co-founded the Giving Pledge in 2010 with Melinda French Gates and Warren Buffett; Not a signer
Foundation: Gates FoundationFormerly the Bill & Melinda Gates Foundation; renamed in 2025. He is trustee of the Gates Foundation Trust; Peterffy FoundationEstablished by Peterffy and run by his children; funds the Living Forest Project, Reweaving the Web and One Small Planet
Lifetime giving: $63.9BGates Foundation, 31 Dec 2025. Joint total given by Bill Gates and Melinda French Gates to the foundation from inception through 2025; no Gates-only figure is published; Not stated

Role now: Founder, no executive roleChair of the Gates Foundation; technology advisor to Microsoft's CEO; Chair of the boardFounder and chairman of Interactive Brokers
Successor: Steve Ballmer succeeded him as Microsoft CEO in 2000; Satya Nadella is now chairman and CEONo Gates family member is named in a Microsoft executive role in the cited sources; Milan Galik succeeded him as CEO in 2019His son William Peterffy, CEO of One Small Planet, is an Interactive Brokers director
Public office: None found; None found
Legal record: 2004: US District Court for D.C. (DOJ case at the FTC's request)A consent final judgment in a case over a Hart-Scott-Rodino premerger notification violation ordered him to pay $800,000 in civil penalties, without trial or adjudication of facts or law.; 1980: American Stock ExchangeSettled an exchange disciplinary matter over exceeding options position limits (Rule 904) with a $500 fine, per his FINRA BrokerCheck report.