Google's public market capitalization exceeding $4.3 trillion as of early October 2026 underpins the 79% market-implied probability that it will hold a higher valuation than OpenAI and Anthropic combined on December 31. This scale reflects stable revenue from advertising and cloud services, contrasting with the private AI labs' combined valuations near $1.8 trillion—OpenAI at an $852 billion confirmed level with implied figures around $930 billion amid talks for a $1.4 trillion round, and Anthropic at $965 billion post its May Series H. Rapid revenue run-rate growth at both startups and Anthropic's planned IPO have narrowed gaps historically but remain insufficient to overcome Alphabet's size in the brief window to year-end. Key near-term catalysts include any final funding closes or IPO filings, though these are unlikely to materially alter the hierarchy given current trajectories.