Anthropic’s active preparation for a mid-November 2026 debut, including confidential S-1 filing and roadshow plans targeting trading before Thanksgiving, drives the overwhelming market-implied odds favoring it over OpenAI. Recent reporting confirms Anthropic aims for a roughly $2 trillion valuation after showing third-quarter results, despite large reported losses and heavy compute commitments. OpenAI CEO Sam Altman has explicitly ruled out any 2026 listing, citing the need to address AI safety and alignment concerns in its large language models before facing public scrutiny, with the company instead pursuing additional private funding rounds. Key upcoming catalysts include Anthropic’s formal marketing phase around November 9 and any shifts in OpenAI’s internal safety timeline that could theoretically accelerate plans, though current statements make that unlikely. Market volatility or extended SEC review remain plausible delay risks for the leader.