Anthropic’s confidential SEC filing on June 1, 2026, has driven the 75.5% market-implied probability that it will complete an initial public offering ahead of OpenAI. The Claude developer’s recent engagement with major banks and preparations for a potential fall listing provide a procedural lead in the race to public markets, allowing earlier access to capital and liquidity for employees amid intense competition in large language model development. OpenAI continues to work with Goldman Sachs and Morgan Stanley on its own draft prospectus and targets a September or fourth-quarter window, yet lacks a filed registration statement and faces additional internal considerations tied to its corporate structure and heavy infrastructure spending. Traders view Anthropic’s concrete filing step as the decisive near-term catalyst, though both timelines remain subject to SEC review, market conditions, and execution risks typical of major AI company listings.