Billionaire investor Bill Ackman said Pershing Square is unlikely to invest in Anthropic, despite calling the frontier AI model maker an exceptional company. Speaking to Bloomberg TV on Wednesday, Ackman praised Anthropic’s revenue and valuation growth and the quality of its Claude product. He said Pershing Square generally favors businesses whose long-term performance is easier to predict, citing Microsoft, S&P Global, Visa and Mastercard, rather than companies growing rapidly while consuming substantial capital. Ackman also questioned whether frontier models can retain market share as open-source and open-weight models gain influence. His comments come as Anthropic targets an initial public offering later this year. The company has not publicly released its customary IPO filing, but a Reuters report earlier this week described a leaked copy showing 2025 revenue rose 12 times to nearly $4.6 billion while net losses reached $42 billion. Anthropic is targeting a $2 trillion valuation in the offering. The success of potential public debuts by Anthropic and rival OpenAI will depend on whether investors believe revenue can eventually exceed spending. Pershing Square still has exposure to the AI sector through shares of Meta, Amazon and Microsoft, according to an August filing.