OpenAI holds a 60% market-implied probability over Anthropic for delivering the next Millennium Prize solution, driven by its September 2026 Navier-Stokes resolution using an internal frontier model and roughly 10,000 coordinating AI agents over 88 hours, followed by formal Lean verification. That result, plus an early October release of 722 papers covering 372 result families across number theory, topology, and other fields, underscores OpenAI’s scaled agentic approach and compute investment in mathematical reasoning. Anthropic contributed to concurrent work on a related forced Euler problem via its own model but has not matched OpenAI’s breadth or claimed a full Millennium Prize outcome. Traders are watching Clay Institute scrutiny of the Navier-Stokes claim, potential follow-on formalizations, and any new internal model announcements as near-term catalysts that could shift the edge.