Billionaire investor Bill Ackman called Anthropic an exceptional company but said Pershing Square is unlikely to invest in the frontier AI model maker. In a Bloomberg TV interview on Wednesday, Ackman praised Anthropic's revenue growth, valuation increase and Claude product, while questioning whether frontier models can retain an advantage over lower-cost open-source and open-weight alternatives. His comments come as Anthropic targets a public debut later this year without having publicly filed its customary IPO paperwork. A leaked filing reported by Reuters showed revenue grew 12 times in 2025 to nearly $4.6 billion, while net losses reached $42 billion. Anthropic is targeting a $2 trillion valuation, making investor confidence in future spending and revenue growth central to the offering. Ackman said Pershing remains invested in Meta, Amazon and Microsoft, and two analysts have questioned the financial math behind Anthropic's plans.