Anthropic's May 2026 Series H round, which raised $65 billion at a $965 billion post-money valuation, underpins the 98.4% market-implied odds that it will rank as the largest private company by valuation at month-end. This priced transaction, backed by major investors including Altimeter and Sequoia, outpaces OpenAI's most recent mark near $852 billion and leaves ByteDance, Stripe, Databricks, and others well behind on official rounds and secondary prints. Strong revenue momentum, with annualized run rates reaching $65 billion and enterprise adoption of the Claude large language model family, reinforces trader consensus on its lead. An IPO targeted for November could shift its status, yet realistic near-term challenges remain limited to an unexpected rival funding event or secondary-market repricing before October 31.