Polymarket Fable model odds collapse to 38% after earlier surge to 70%
Polymarket traders cut the probability of an Anthropic Fable model release by month-end to 38% on October 23, a 30 percentage point drop over 24 hours. The contract specifies version 5.2 or later. The plunge reverses a move to 70% odds just over a week earlier on an October 17 deadline contract, leaving three overlapping Fable contracts with staggered dates and version triggers live on the platform. The whipsaw leaves traders exposed to time decay and oracle ambiguity across the fragmented contracts.
The 32-point roundtrip in under two weeks exposes the liquidity trap in thin AI-timeline markets. Traders who bought the October 17 surge near 70% and rolled into later-dated contracts now face mark-to-market losses with no fresh information from Anthropic. The three overlapping Fable contracts with different version triggers and deadlines fragment an already shallow book, so a single large order can reprice the whole curve.
That volatility is fee revenue for Polymarket but execution risk for directional holders. Anthropic must manage public price signals it does not control, with conflicting contract terms complicating any eventual release. The platform that stabilizes as the reference venue for AI bets will capture structured product volume, but these swings instead warn desks away from sizing positions.