Meta's public market capitalization stands near $1.85 trillion as of early October 2026, reflecting strong revenue momentum, AI-driven product launches such as the Muse agent, and a forward P/E around 27x amid consistent earnings beats. OpenAI's latest confirmed post-money valuation reached $852 billion following its March funding round, with secondary indications near $900 billion and early-stage talks for a $30 billion raise at roughly $1.4 trillion pre-money; however, those discussions remain preliminary and an IPO is not expected until 2027. This gap underpins the 93.5% market-implied probability favoring Meta on December 31. A completed OpenAI round at elevated terms or sharp Meta share-price weakness ahead of its October 28 earnings could narrow the differential, though historical precedent for rapid private-to-public valuation convergence remains limited.