Anthropic (ANTH.PVT) publicly filed its S-1 investor prospectus on Monday, ahead of its planned initial public offering later this fall under the ticker symbol "ANT."The AI lab, helmed by CEO Dario Amodei, has exploded in popularity thanks to its Claude Code AI coding tool and Claude Cowork enterprise offering.As of May, Anthropic was valued at $965 billion, more than rival OpenAI's (OPAI.PVT) $852 billion valuation in March.