OpenAI’s decision to delay its IPO until at least 2027, driven by CEO Sam Altman’s emphasis on advancing AI safety and alignment before facing public-market scrutiny, underpins the 56.6% implied probability for a closing market cap above $1.5 trillion. Private-market activity supports this view, with the firm’s March 2026 round setting an $852 billion post-money valuation and early talks underway for a $30 billion-plus pre-IPO round at roughly $1.4 trillion pre-money. Recent annualized revenue estimates near $50 billion, alongside a confidential S-1 filing and 2027 target from CFO Sarah Friar, reinforce expectations of substantial growth by listing. The 20.9% chance assigned to no IPO by end-2027 reflects ongoing regulatory, competitive, and execution risks that could extend the private phase.