Traders assign Anthropic a 99.4% implied probability of ending September as the largest private company because its current valuation, bolstered by recent large language model releases and strategic partnerships in the artificial intelligence sector, sits well ahead of peers. With only days remaining until the resolution date, limited room exists for material valuation shifts from funding rounds or market moves. Other contenders such as ByteDance, Revolut, and Databricks trail significantly on established metrics. A realistic challenge would require an unexpected regulatory action, major data breach disclosure, or sudden competitor funding announcement large enough to close the gap before month-end—developments that appear improbable on current timelines.