Alphabet's roughly $4.3 trillion market capitalization provides the dominant anchor for the 78.5% trader-implied probability that it will exceed the combined valuation of OpenAI and Anthropic by year-end. Recent secondary marks place OpenAI near $900 billion to $1.2 trillion and Anthropic around $1.39 trillion, with OpenAI targeting a $1.4 trillion private round and Anthropic preparing an IPO that could test $2 trillion; even optimistic sums remain well below Alphabet's diversified revenue base from search, cloud, and advertising. Steady Alphabet share prices and limited near-term catalysts for the private AI firms reinforce the current consensus, though Anthropic's expected November listing and any follow-on funding announcements could introduce volatility in the final weeks.