Anthropic’s advanced IPO timeline, with formal marketing eyed for the week of November 9 and trading targeted before Thanksgiving 2026 at a potential $1.8–2 trillion valuation, drives the 95.4% market-implied odds favoring it over OpenAI. The company confidentially filed its S-1 in June, recently held pre-IPO investor meetings, and disclosed rapid revenue growth alongside substantial compute commitments in leaked prospectus details. OpenAI’s CEO Sam Altman explicitly ruled out a 2026 listing in September, citing the need to address AI safety and alignment concerns before going public, while the firm pursues additional private funding rounds instead. Trader consensus reflects these concrete scheduling differences, though realistic shifts could arise from Anthropic facing market volatility or regulatory scrutiny that delays its debut, or from OpenAI resolving safety priorities faster than anticipated and accelerating its own process into 2027.