Anthropic holds a strong lead in the race to IPO first, with traders assigning it an 86.5% implied probability on the strength of concrete process milestones and financial momentum. The company confidentially filed its draft S-1 registration statement with the SEC on June 1, 2026, shortly after closing a $65 billion Series H round at a $965 billion post-money valuation, and has lined up major underwriters for a potential September or October debut. Its enterprise-focused Claude models have driven faster revenue growth—estimated near $47 billion in annualized recurring revenue—compared with OpenAI, giving Anthropic clearer visibility into a near-term listing. OpenAI filed its own confidential S-1 days later but faces greater execution risk, with credible reporting pointing to possible slippage into 2027 amid governance restructuring and a more cautious approach to timing. Recent updates, including Anthropic’s accelerated window and OpenAI’s reported preference for waiting until market conditions stabilize, have reinforced the gap. Key near-term catalysts include any public S-1 amendments, final pricing decisions, and macroeconomic signals that could either compress or extend both timelines. Traders view Anthropic’s earlier filing and superior private-market traction as decisive advantages in a process where regulatory review and investor appetite remain the primary variables.