Traders see the highest implied odds clustered on October 5–6 because leaks from early September described a fresh Fable pretraining run slated for late September or early October, with routing tests in mid-September suggesting an internal successor to the September 1 Fable 5.1 release. Anthropic’s September 22 announcement of Sonnet 5.5 and Haiku 5.5 without mentioning Fable has kept expectations alive while adding uncertainty about exact timing or naming. The wide spread across mid-to-late October dates reflects the absence of any official model card, API identifier, or pricing update, typical for Anthropic’s iterative releases where internal testing and safeguard calibration often shift schedules. Key near-term catalysts include potential API catalog changes or developer announcements that could resolve the market quickly.