Anthropic could surpass SpaceX for largest 2026 IPO, prediction markets show

For most of this year, SpaceX’s IPO looked like an untouchable record. Then Anthropic quietly filed a confidential S-1 with the SEC, and suddenly prediction markets have a real race on their hands. Polymarket currently prices SpaceX as the favorite to hold the title of largest 2026 IPO by market cap, with roughly 55% odds. Anthropic sits just behind at 44-45%. That gap sounds comfortable until you consider where the probability was a few months ago: SpaceX commanded around 94% in August 2026. The AI company didn’t just close the gap, it nearly erased it. The numbers making investors pay attention SpaceX’s June 2026 IPO was not a modest debut. The company priced shares at $135 each, raised $75 billion, and landed a valuation of approximately $1.77 trillion. Shares climbed to around $225 intraday before settling back to trade near $142. By any historical measure, that is the largest IPO on record. Anthropic is aiming higher. The company filed its S-1 confidentially on June 1, 2026, and is targeting an IPO as early as October with a valuation north of $2 trillion. Its most recent post-money valuation, following a May 2026 funding round, stood at $965 billion, meaning the public offeri...