Steve Eisman, the investor famous for betting against the U.S. housing market before the global financial crisis, is now sounding the alarm on a hidden vulnerability in the artificial intelligence boom.
Eisman says the entire AI investment thesis rests uncomfortably on the commercial success of just two private companies: OpenAI and Anthropic.
Speaking on CNBC’s “Fast Money,” Eisman argued that the two AI startups account for roughly 70% of AI-related revenue at Microsoft (NASDAQ: MSFT), Amazon (NASDAQ: AMZN), Alphabet’s Google (NASDAQ: GOOGL), and Oracle (NYSE: ORCL).
He added that OpenAI and Anthropic together represent as much as 25% to 35% of cloud revenue at those same technology giants, underlining how exposed the sector truly is.
“The futures of these massive companies, in a sense, are a bet that OpenAI, Anthropic are going to succeed,” Eisman said on the program, making clear the stakes involved for investors holding big tech stocks.
Eisman identified China as the most serious threat to that bet, pointing to cheaper Chinese open-source AI models that he believes are already gaining meaningful market share globally.
“The Achilles’ heel of this whole story … is if something bad happens to Anthropic and OpenAI … the Chinese open-end models, open-weight models are much cheaper,” Eisman warned, adding that aggressive market share gains could trigger a damaging price war across the industry.
A sustained price war would directly undermine the financial logic behind the enormous capital expenditure programs that hyperscalers have committed to, which are premised on AI workloads generating healthy long-term returns.
Eisman also cautioned that many investors may be more concentrated in the AI trade than they realize, since even a traditional portfolio of stocks and bonds can carry significant indirect exposure through big tech’s dominance of major indexes.
The concern over concentration is supported by official index data, with the 10 largest companies in the S&P 500 accounting for approximately 36.4% of the index, according to S&P Dow Jones Indices.
The Federal Reserve flagged a similar concern in its May financial stability report, noting that large-cap valuations remained near the upper end of their historical range and that AI-related risks ranked among the biggest threats identified by market participants.
Michael Burry, another investor whose housing market bet was documented in “The Big Short,” has taken a notably more aggressive bearish stance, questioning whether genuine end-customer demand underpins current AI spending or whether much of it relies on circular financial arrangements.
Burry has moved to place bearish bets against some of the biggest beneficiaries of the AI investment cycle, including Nvidia (NASDAQ: NVDA), as well as broader positions against the semiconductor sector more widely.
Eisman’s warning arrives at a moment when Wall Street remains broadly bullish on AI infrastructure, making his caution about OpenAI and Anthropic concentration a notable dissenting voice in an otherwise optimistic market narrative.
