Meet James: The Mathematician and Code Breaker Behind the Billionaire Hedge Fund 🚀

The Medallion Fund continued to outperform, never recording a negative quarter since 1999. From 1989 to 2018, it achieved an average annual return of 39.1%, net of fees. For comparison, Warren Buffett’s Berkshire Hathaway averaged 20.5% annually, while Ray Dalio’s fund averaged 12%. Medallion’s success allowed it to charge high fees—5% of invested capital and up to 44% of profits—yet still deliver outstanding returns to its investors.

By 1993, the fund capped its capital at $10 billion, and in 2003, Simons decided to close it to new external investors. Medallion became a fund almost exclusively for Renaissance employees and partners.

In 2005, Renaissance launched the Renaissance Institutional Equities Fund (RIF) for external investors, but it never matched Medallion's performance. RIF fell 16% in 2008 and 6.17% in 2009. Meanwhile, Medallion thrived, gaining 98.5% in 2000 and 82.4% during the 2008 financial crisis. Even in more recent years, it outperformed the market, with a 45% gain in 2018 while the S&P 500 dropped over 6%.

In 2010, at the age of 82, Jim Simons retired, leaving Brown and Mercer as co-CEOs of Renaissance Technologies. Brown remained in charge after 2017. Simons spent his later years as a philanthropist, donating billions to fund scientific research. He passed away in 2024 at the age of 86, with an estimated net worth of $31.4 billion.