Key Takeaways
- • The Bloomberg Billionaires Index shows tech titans added a record $845 billion through September 2026, driven by the AI boom, while billionaires outside tech lost a combined $62 billion over the same period.
- • Americans have held all 10 top spots on the index since Sept. 10, the first time since Bloomberg began tracking in 2012, and about 100 of the world's 500 richest people owe their fortunes to technology according to Bloomberg News wealth reporter Dylan Sloan.
- • S&P Global research found the 10 largest S&P 500 companies held almost 40% of the index by mid-2025, a concentration level last seen in the mid-1960s.
- • Wealth figures measure fortunes, not stock returns, and include private holdings such as stakes in Anthropic that retail investors cannot buy.
- • Lone Pine Capital's flagship hedge fund erased almost all of a 44% gain through June after AI bets reversed, and Ray Dalio issued an AI bubble warning tied to AI debt and rising interest rates.
Summary
The Bloomberg Billionaires Index shows the AI boom helped technology billionaires add a record $845 billion through September, while billionaires outside the technology sector lost a combined $62 billion over the same period. The publication cautions that these figures measure personal fortunes rather than stock returns, and that some of the gains come from private AI developers such as Anthropic, which retail investors cannot buy.
Bloomberg News wealth reporter Dylan Sloan said about 100 of the world's 500 richest people owe their fortunes to technology. He cited Taiwan's King Slide, which began in the 1980s making drawer slides and now supplies slides for data center server racks; its founder entered the index at $9.5 billion. Americans have held all 10 top spots since Sept. 10, a first since Bloomberg began tracking in 2012. Sloan also noted that more new entrants now come from China, including founders of AI labs such as DeepSeek and MiniMax.
Bloomberg values private stakes similarly to public ones, applying liquidity discounts in some cases. It added all seven Anthropic co-founders in June after a funding round valued the company at $965 billion.
Concentration in the equity market is also elevated. According to S&P Global research, the 10 largest S&P 500 companies held almost 40% of the index by mid-2025, a level last seen in the mid-1960s. Standard S&P 500 index funds track those weights. The same research found that the top 10 from 1965, which then represented almost half the index, fared poorly over the following 60 years, although the S&P 500 gained about 7.4% a year over that span excluding dividends.
The concentration risk has already affected active managers. Lone Pine Capital's flagship hedge fund erased almost all of a 44% gain through June after AI bets reversed. Separately, Bridgewater Associates founder Ray Dalio issued an AI bubble warning last week, linking the risk to AI debt and rising interest rates.
The ranking records fortunes already made rather than future returns. For index holders, the open question is whether the largest AI-linked stocks continue to carry the S&P 500.
Bloomberg News wealth reporter Dylan Sloan said about 100 of the world's 500 richest people owe their fortunes to technology. He cited Taiwan's King Slide, which began in the 1980s making drawer slides and now supplies slides for data center server racks; its founder entered the index at $9.5 billion. Americans have held all 10 top spots since Sept. 10, a first since Bloomberg began tracking in 2012. Sloan also noted that more new entrants now come from China, including founders of AI labs such as DeepSeek and MiniMax.
Bloomberg values private stakes similarly to public ones, applying liquidity discounts in some cases. It added all seven Anthropic co-founders in June after a funding round valued the company at $965 billion.
Concentration in the equity market is also elevated. According to S&P Global research, the 10 largest S&P 500 companies held almost 40% of the index by mid-2025, a level last seen in the mid-1960s. Standard S&P 500 index funds track those weights. The same research found that the top 10 from 1965, which then represented almost half the index, fared poorly over the following 60 years, although the S&P 500 gained about 7.4% a year over that span excluding dividends.
The concentration risk has already affected active managers. Lone Pine Capital's flagship hedge fund erased almost all of a 44% gain through June after AI bets reversed. Separately, Bridgewater Associates founder Ray Dalio issued an AI bubble warning last week, linking the risk to AI debt and rising interest rates.
The ranking records fortunes already made rather than future returns. For index holders, the open question is whether the largest AI-linked stocks continue to carry the S&P 500.
Go deeper than the headline
Research every firm in this story, track the ones that matter and get the daily briefing — free for 7 days.