OpenAI’s September 2026 announcement of a Lean-formalized proof establishing finite-time singularity for the 3D incompressible Navier-Stokes equations under smooth forcing has anchored trader sentiment, reinforced by the company’s explicit decision not to pursue the Clay Prize and the absence of any official retraction through mid-October. The multi-agent effort, run on an unreleased model exceeding GPT-6 Astra capabilities, produced both a 166-page manuscript and machine-checked formalization, giving the result more credibility than typical AI math claims despite a priority dispute with mathematicians Buckmaster and Alpöge and noted mismatches between natural-language and Lean versions. Ongoing peer review and OpenAI’s rapid withdrawal of three unrelated preprints for sign errors illustrate its willingness to correct flaws, yet no comparable gap has surfaced for Navier-Stokes itself. A late-year verification failure or internal acknowledgment of substantive error remains the clearest path to retraction before year-end.