Polymarket is pricing a 77% chance that Anthropic will release its next Claude Opus model on Sept. 22, 2026, according to a PPP prediction-market monitoring signal that said the probability rose 50% in 24 hours. Anthropic has not officially announced a release date or version number. The market counts only a new model that Anthropic explicitly names Opus, such as a potential Claude Opus 5.1, Opus 5.5 or Opus 6; Sonnet, Haiku, Fable and Mythos do not qualify unless Anthropic formally assigns one of those models the Opus name. Settlement uses the calendar date in U.S. Eastern Time and requires genuine public access. An open beta or public rolling waitlist qualifies, while a closed beta, invitation-only access, private access, a placeholder or a mistaken model listing does not. Anthropic’s official information is the primary settlement reference, supplemented by credible media reports. Earlier market snapshots put the probability of a release by Sept. 24 at about 83%, Sept. 27 at 90%, Sept. 30 at 94%, Oct. 31 at about 98% and year-end at more than 99%. The market opened Sept. 15 and had recorded about $240,925 in volume. The expectations have been linked to unverified reports of stealth testing of a model codenamed claude-wafer-eap, possibly Claude Opus 5.5, amid Anthropic’s accelerated release schedule and wider debate over the pace and safety of frontier-model development.