Anthropic leads Polymarket odds at 54.1% for the largest 2026 IPO by market cap, ahead of SpaceX at 44%, driven by its planned November listing targeting up to a $2 trillion valuation—exceeding SpaceX’s June IPO priced at $135 per share for a $1.77–1.8 trillion debut that raised a record $75 billion. Anthropic’s rapid revenue trajectory, with annualized run rates climbing toward $65–120 billion amid strong demand for its Claude models, supports trader consensus on a higher implied market cap at debut, even as the firm reports substantial losses and infrastructure commitments. SpaceX’s post-IPO trading near $2 trillion reflects its Starlink and launch operations but caps its 2026 IPO size, while xAI’s merger into SpaceX removes it as a standalone contender and other candidates like OpenAI face delayed timelines. Upcoming catalysts include Anthropic’s roadshow timing and final pricing relative to prevailing Treasury yields and equity multiples.