Big short investor Steve Eisman: Anthropic and OpenAI are the Achilles' heel of AI trading.

The market is eagerly anticipating the IPO moments of OpenAI and Anthropic, but in the eyes of renowned short-seller Steve Eisman, these two AI giants are precisely the most vulnerable link in the entire AI trading chain. Anthropic is racing towards its initial public offering (IPO), with its valuation and fundraising scale expected to surpass the record-breaking IPO of SpaceX this summer. Reports indicate that its valuation could reach as high as $2 trillion, and once it materializes, this developer of the Claude model will join the ranks of the world's most valuable companies. However, Eisman, who is known for shorting the real estate market against the trend in "The Big Short," is concerned that the current AI trading is overly dependent on the fortunes of just two companies. If theres an Achilles' heel to the whole story, it lies with Anthropic and OpenAIif anything goes wrong with these two, Eisman said in an interview. He warned that if cheaper models from China begin to capture market share, it could trigger a price war, and thats when well be in trouble. After years of driving stock indices to new highs, AI trading once again proved its status as a market engine in 2026, but concerns about the sustainability of this investment craze continue to heat up. The problem is, as far as I know, about 70% of the AI revenue of giants like Microsoft, Amazon, Google, and Oracle comes from Anthropic and OpenAIjust these two, Eisman said. In a sense, the future of these giants essentially bets on the success of OpenAI and Anthropic. Eisman is not the first to express concerns about the financial health of these two AI giants. Independent researcher and journalist Ed Zitron warned earlier this summer that OpenAI could become the Lehman Brothers of the AI tradeif it encounters setbacks, it could pose a systemic risk that drags down other companies. Meanwhile, the rise of Chinese open-source weight models, represented by Kimi K3, sparked panic on Wall Street last month, causing chip stocks to plummet due to worries about intensified competition in the AI market. However, like the situation when DeepSeek was launched in January 2025, the declines have largely recovered, and market sentiment has calmed. The Philadelphia Semiconductor Index has gained 75% year-to-date. Despite his concerns, Eisman clarified that he is not yet willing to make a judgment on the price war between OpenAI, Anthropic, and their Chinese rivalsat least until more information about the financial health of the two companies is obtained. Just wait for Anthropic to go public; then we can see the real data, and track their performance every quarter, he said. Until then, it's all just hearsay.