Polymarket and Kalshi diverge sharply on Anthropic IPO odds
Polymarket traders are pricing Anthropic at 63% to top SpaceX as 2026's largest IPO. The Kalshi prediction market separately prices an Anthropic IPO this year at 90% probability. The pricing gap between the two CFTC-regulated platforms reflects different contract designs: Polymarket compares Anthropic against SpaceX for largest offering, while Kalshi prices only the likelihood of any Anthropic debut. Both markets signal shifting sentiment toward AI companies over aerospace ventures.
The 27-point spread between Polymarket and Kalshi is a live test of whether prediction markets on the same underlying event can sustain divergent prices. Traders who understand the contract differences — Polymarket's conditional ranking versus Kalshi's binary debut bet — can spot real or illusory arbitrage. Polymarket, the Anthropic contract builds on its Paramount-Skydance and Tesla-SpaceX corporate events, where retail flow has already shown it can spike and fade.
Thin liquidity on long-duration IPO markets means wide spreads and stale quotes, so a 63% price may reflect last trade rather than current consensus. Kalshi's 90% reading looks more precise but rests on a simpler question that avoids the size-comparison problem entirely. Neither platform publishes fillable order books or post-trade size, so traders cannot verify actual depth. The divergence matters most for platforms competing to become the reference price for tech debuts: the venue that produces the most credible, tradeable number wins issuer and media attention, even if the methodology stays opaque.