Anthropic's advanced IPO preparations, including its June 2026 confidential S-1 filing and ongoing marketing timeline targeting a November listing after the U.S. midterms, stand in contrast to OpenAI's explicit postponement of any public debut until 2027. Trader consensus at 96% implied probability for Anthropic reflects CEO Sam Altman's repeated statements prioritizing AI safety and alignment work over an ill-timed listing, alongside OpenAI's pursuit of additional private funding. While the high odds capture this clear separation in timelines, realistic shifts could arise from further regulatory scrutiny of frontier AI models, unexpected market volatility delaying Anthropic's roadshow, or rapid resolution of OpenAI's safety milestones enabling an accelerated 2026 process.