Anthropic’s Series H and Draft S-1 Point to a Bigger Shift in Frontier AI

On May 28, 2026 , Anthropic announced a $65 billion Series H at a $965 billion post-money valuation . On June 1, 2026 , it said it had confidentially submitted a draft S-1 to the SEC, which means it now has the option to go public later if conditions are right. Those look like normal company-building signals. But the more interesting story is not the valuation, and not the IPO option by itself. It…