Kalshi and Polymarket diverge 59 points on OpenAI IPO odds as both launch AI valuation markets
Kalshi traders are pricing 88% odds that OpenAI announces an IPO in 2026 and an 85% probability it goes public before Anthropic, according to News.kalshi.com and Seeking Alpha reports published May 21, 2026. The repricing follows Wall Street Journal reports of a confidential filing. Meanwhile, Polymarket traders price a 70% chance of a year-end OpenAI IPO according to the platform's official X account — a 41-point gap from the 29% figure cited by LinkedIn on May 13 — and have assigned an 11% probability that Anthropic hits a $4 trillion market cap on debut. Polymarket launched private-company trading contracts on Anthropic, OpenAI, and SpaceX on May 19, with traders pricing a combined $4.3 trillion valuation for all three by June 30 and expecting SpaceX, OpenAI, and Anthropic to surpass Berkshire Hathaway's $1.4 trillion valuation at debut.
Kalshi must now defend its standalone sourcing model against Polymarket's Nasdaq-backed data partnership. Any persistent pricing gap on the same OpenAI and Anthropic contracts will cost Kalshi institutional flow as traders arbitrage the two venues.
Joins Polymarket's existing private-company launches with Nasdaq Private Market and SpaceX on the same day, making this the third distinct pre-IPO data partnership or contract type the crypto-native platform has introduced since Sunday.