Anthropic’s next Fable-series large language model (5.2 or higher) faces closely matched Polymarket odds around mid-November because the September 1 release of Fable 5.1 established a roughly quarterly cadence while unconfirmed leaks of a Fable 5.5 identifier and fleeting Azure catalog entries have not produced official confirmation. Traders weigh Anthropic’s pattern of frontier-model updates against the absence of announced benchmarks, pricing changes, or API availability, with competitive pressure from other labs’ recent releases adding uncertainty. Key swing factors include any developer-conference announcements or verified capability demonstrations that could shift the implied release window before the end of the month.