Anthropic's active progress toward a late-2026 Nasdaq listing, including its June 2026 confidential S-1 filing and recent prospectus details showing revenue run rates exceeding $100 billion, drives the 96.2% market-implied probability it will IPO before OpenAI. In contrast, OpenAI CEO Sam Altman stated in September 2026 that a 2026 listing would be ill-advised amid AI safety and alignment priorities, shifting focus to private fundraising at around $1.4 trillion valuation instead. Traders see limited near-term reversal risk given Anthropic's banker-led timeline targeting November or earlier, though delays from SEC reviews, market volatility, or both firms' compute-intensive scaling could still extend timelines into 2027.