Codex leak suggests imminent GPT-5.5 announcement

Odds of a GPT-5.5 release by April 23 have hit 93% YES on Polymarket after a leak in the Codex tool suggested an announcement today, up from 64% a week ago.

The April 30 contract is at 98.9% YES, up from 89% a week ago. The June 30 market sits at 99.4% YES. The biggest term structure shift is a 6-point jump between the April 23 and April 30 contracts, which concentrates trader conviction around an imminent announcement rather than a later date.

The April 23 market has $74,705 in actual USDC traded, with only $930 needed to move the price five points. That’s reasonably liquid but still thin enough for large trades to cause sharp moves. The largest recent swing was a 7-point spike at 4:17 PM, likely driven by speculators front-running the expected livestream.

A YES share at 93¢ pays $1 if GPT-5.5 is announced today. The 7-cent upside is a direct bet on the Codex leak being accurate. The market is pricing the leak as credible despite it originating from a tier-3 source, which means the remaining risk is concentrated in the possibility of a delayed or canceled announcement.

Watch Sam Altman’s Twitter and the OpenAI status page for confirmation. Either would be a definitive signal and could push the remaining contracts toward resolution.

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