OpenAI's explicit delay of any IPO until 2027 at the earliest, driven by CEO Sam Altman's emphasis on AI safety and alignment for large language models, has created the primary catalyst behind the 95.3% market-implied odds favoring Anthropic listing first. Anthropic confidentially filed its S-1 in June, advanced its prospectus, and now targets a November 2026 debut after recent timeline shifts to incorporate third-quarter results, supported by rapid revenue growth exceeding $65 billion annualized and competitive positioning in the AI sector. Trader consensus reflects these confirmed timelines and OpenAI's private funding flexibility, though realistic disruptions remain possible from regulatory reviews, market volatility, or unforeseen safety-related pauses that could compress or extend the gap between the two frontier labs.