Goldman Sachs holds a narrow edge over Morgan Stanley in the lead bank market for OpenAI’s eventual IPO because both firms have served as primary bookrunners since the company’s confidential S-1 filing in June 2026 and its ongoing $30 billion bridge round. Recent precedent from Anthropic’s October 26 S-1, which formally named Goldman lead left and Morgan Stanley stabilization agent, has reinforced trader consensus around Goldman’s allocation influence in large AI listings. The 45.5%–39.5% implied probabilities reflect this tight competition, with limited roles for other banks in supporting capacities. Key swing factors include OpenAI’s next regulatory disclosures and any shifts in lead-left designation ahead of a 2027 listing.