OpenAI CEO Sam Altman's testimony on May 12 in Elon Musk's federal lawsuit against the company—alleging betrayal of its nonprofit AI safety mission—has driven Polymarket's "Yes" outcome to 100% implied probability, reflecting trader consensus backed by real capital. Altman defended OpenAI's for-profit restructuring, Microsoft's partnership, and rebutted Musk's claims of dishonesty, including Musk's reported demand for 90% equity control, sharpening the trial's focus on AI governance and competitive dynamics between OpenAI and xAI. With the witness appearance confirmed via court records and extensive media coverage, strong consensus stems from this verifiable event fulfilling market criteria. Realistic risks remain minimal but could include rare procedural motions to strike testimony or appeals altering resolution amid the ongoing Oakland trial.