Anthropic’s accelerated path to a mid-November 2026 IPO at $1.8–2 trillion valuation targets is the main factor behind the 68.5% market-implied probability it will achieve the higher closing market cap. Its confidential S-1 filing in June, recent $965 billion private round, and revenue run-rate surging past $65–100 billion have positioned the Claude developer for a debut that could eclipse SpaceX’s record, even as the prospectus highlights heavy compute spending and operating losses. OpenAI, by contrast, has deferred any 2026 listing to prioritize AI safety and alignment work, instead pursuing a $30 billion-plus private round at roughly $1.4 trillion that functions as bridge financing ahead of a likely 2027 debut. Traders view the sequencing and Anthropic’s nearer-term pricing as decisive, though OpenAI’s rapid enterprise revenue growth and potential later scale remain swing factors.