Anthropic’s confidential SEC filing in June 2026 and active preparations for a November listing, including prospectus details and marketing plans ahead of U.S. midterms, have driven the 96.5% market-implied probability that it will IPO before OpenAI. OpenAI CEO Sam Altman has repeatedly stated since September that the company will not go public in 2026, prioritizing safety and alignment work on advanced large language models over meeting investor expectations during a period of rapid capability shifts. This stance has led OpenAI to pursue additional private funding rounds instead. While Anthropic’s timeline could still slip due to regulatory reviews or market conditions, OpenAI’s explicit multi-year safety focus makes a reversal before late 2027 unlikely.