Two accounts that have performed notably well in the Anthropic section predict the new Fable model will be released this week.

According to PolyBeats monitoring, on the prediction market Polymarket, the probability of the next-generation Fable model being released this week is currently 60%. In official public documentation, the latest verifiable Fable is still Claude Fable 5.1, launched on September 1.

dublyash2 bought $2.6k "Yes" at a purchase probability of 58.64%. They have made 9 trades in the Claude sector in total, with a win rate of 56%, PnL +$11.4k, and this bet is 10.15 times their median bet.
0xC42d02AFE568A863C7 bought $2.12k "Yes" at a purchase probability of 65.74%. They have made 9 trades in the Claude sector in total, with a win rate of 78%, PnL +$2.0k, and this bet is 4.83 times their median bet.

Starting in September, rumors first spread on X about "a new round of Fable pretraining, temporarily called 5.2," with the window mostly stated as "late September to early October" for the new model launch; starting September 10, the same narrative changed to "Fable 5.5," aligning with the Opus/Sonnet/Haiku naming. On October 9, an account claimed to have briefly accessed a stronger Fable and, after permissions were revoked, expected it to be "publicly released next week."

On October 13, the account leo (@synthwavedd) said, "Fable 5.5 is scheduled for this week; it may not be ruled out today and could also be delayed to midweek"; Chubby (@kimmonismus) replied, "Trust Leo."