Warren Buffett disciple Guy Spier built career on value investing. A rare cancer changed everything

Noted value investor Guy Spier first gained the public's attention in 2007 when he and a partner paid more than $650,000 at a charity auction to have lunch with the world's most famous value investor, Warren Buffett . Spier, who calls Buffett his hero, launched his Zurich-based fund Aquamarine in 1997. He mimicked the Oracle of Omaha's investing philosophy , anchored on the premise of compounding interest. Spier hoped the approach would help him build a similarly long-lasting, albeit more modest, investing legacy for Aquamarine. And for years, it worked. From 1997-2025, Aquamarine's total returns outpaced the S&P 500, long seen as the ultimate benchmark for a fund's success. But in November 2024, while returning from a ski trip with his family, a medical emergency forced Spier to confront the realities of his own mortality, and redefine how he decides what holds value in life. "It was a super cold day in November, and on the car journey back to Zurich, I had a grand mal seizure," Spier recalled in an interview for the CNBC Cures' podcast "The Path with Becky Quick." "I was sitting next to my wife in the car. She didn't know what was going on," Spier said during the interview, which was conducted at the recent Berkshire Hathaway annual shareholder meeting. Spier was flown to a hospital where he was given an MRI. "I wake up the next day and I discover that I've got a brain tumor, and my life changed completely on that date," Spier said. …