Goldman Sachs and Morgan Stanley maintain their dominant positions as the primary underwriters for OpenAI’s eventual IPO, reflecting their early engagement on the company’s confidential S-1 filing in June 2026 and ongoing preparations alongside rival Anthropic. Goldman’s 54% implied probability stems from its recent lead-left role on the record SpaceX offering, broader technology-sector relationships, and execution depth in complex AI valuations, while Morgan Stanley’s 36% share captures its strong AI deal momentum and joint bookrunner status. OpenAI’s decision to defer any listing until at least 2027, driven by safety considerations and capital needs, has introduced timeline uncertainty without altering the bank hierarchy. Secondary banks such as JPMorgan and Citigroup hold minimal odds, consistent with their supporting syndicate roles discussed earlier this year. Traders will watch for any formal lead-left designation or renewed filing updates as the key resolution signals.