Science and Technology Polymarket September 28, 2026
Anthropic's Claude Sonnet 5.5 Release Imminent
Next Claude Sonnet released on...?
Polymarket prices this September 28 at 68%. The reporting broadly agrees.
Anthropic is reportedly on the cusp of releasing its next-generation Claude Sonnet AI model, potentially named Claude Sonnet 5.5, with some reports suggesting a launch date as early as September 28. This anticipated release follows recent A/B testing and partner checkpoint evaluations, indicating the model is nearing public availability. The new Sonnet variant is expected to offer enhanced capabilities, building on Anthropic's established Claude family of large language models. The market tracking this release shows a strong expectation for a September 28 launch, with 68% probability, reflecting the recent surge in reports about its imminent debut.
Background
Anthropic, a leading AI research company, has been steadily developing its Claude series of large language models, with Sonnet serving as one of its key tiers, balancing performance and cost-efficiency. The company recently unveiled Claude Opus 5.5, a separate, more powerful model, but attention is now turning to the next Sonnet iteration. Previous Sonnet models have been widely adopted for various applications, and the anticipation for Sonnet 5.5 stems from its potential to introduce significant improvements for a broad user base. The specific proposition for this market is whether Anthropic will make its next Claude Sonnet model publicly available on September 28.
The precedent
- Anthropic previously launched Claude Opus 5.5, a different model in its Claude series, approximately six days prior to the current reporting.
Context compiled by Crowdtells from the public record — verify before relying on it.
What the coverage agrees on
- Anthropic is preparing to release a new Claude Sonnet model.
- The new model is likely to be named Claude Sonnet 5.5.
- A release could happen very soon, possibly within days.
Where sources diverge
- The exact release date for Claude Sonnet 5.5 is not officially confirmed.
How outlets frame it
- testingcatalog.com: Emphasizes the potential for a launch 'as early as next week' and highlights 'leaks' and 'partner checkpoint tests' as indicators.
- finance.biggo.com: Reports on Anthropic 'reportedly A/B testing' Sonnet 5.5 and includes a specific detail about its potential pricing at '$2 Per Million Input Tokens'.
What to watch
The immediate focus is on official announcements from Anthropic regarding the public launch of Claude Sonnet 5.5. Reports of ongoing A/B testing suggest a release could materialize within days. Observers will be looking for confirmation of public accessibility, whether through an open beta or general availability, to determine if the September 28 date is met. Any further leaks or partner communications could also provide clearer signals of the exact launch timeline.
The numbers behind this
Polymarket prices this September 28 at 68%.
24h +23.5 pts
$38.1K traded · $29.3K in the last day · $51.6K resting liquidity · $7.6K open interest
Resolves on: This market will resolve according to the calendar date (ET) on which Anthropic's next Claude Sonnet model is made available to the general public. Claude Sonnet refers to a model by Anthropic explicitly named Sonnet. Qualifying models include Claude Sonnet 5.1, Claude Sonnet 5.5, Sonnet 6, or any other Sonnet variants. Models under any other name, such as Opus, Haiku, Fable, or Mythos, will not qualify, unless the model is explicitly and officially named Sonnet by Anthropic. A qualifying model must be launched and publicly accessible, including via open beta or open rolling waitlist signups. A closed beta or any form of private access will not suffice. The release must be either…
Pricing Polymarket 68%
Sources
- Anthropic may release Claude Sonnet 5.5 within days testingcatalog.com
- The Claude Sonnet 5.5 leak beating GPT-6 Sol is not what it looks like startupfortune.com
- Introducing Claude Opus 5.5 anthropic.com
- Anthropic unveils Claude Opus 5.5 reuters.com
- Anthropic Reportedly A/B Testing Sonnet 5.5 — $2 Per Million Input Tokens finance.biggo.com
Frequently asked questions
Next Claude Sonnet released on...?
Polymarket prices this September 28 at 68%. The reporting broadly agrees.
What do the sources agree on?
Anthropic is preparing to release a new Claude Sonnet model. The new model is likely to be named Claude Sonnet 5.5. A release could happen very soon, possibly within days.
Where do the sources disagree?
The exact release date for Claude Sonnet 5.5 is not officially confirmed.
When does this market resolve?
This market resolves on: This market will resolve according to the calendar date (ET) on which Anthropic's next Claude Sonnet model is made available to the general public. Claude Sonnet refers to a model by Anthropic explicitly named Sonnet. Qualifying models include Claude Sonnet 5.1, Claude Sonnet 5.5, Sonnet 6, or any other Sonnet variants. Models under any other name, such as Opus, Haiku, Fable, or Mythos, will not qualify, unless the model is explicitly and officially named Sonnet by Anthropic. A qualifying model must be launched and publicly accessible, including via open beta or open rolling waitlist signups. A closed beta or any form of private access will not suffice. The release must be either…
How are these odds set?
Prediction-market odds are prices set by people trading real money on the outcome, so the price reads as the crowd’s implied probability — not a guarantee or financial advice.
AI-written briefing grounded in 5 sources and the live market, edited by Samuel Jo. Odds are crowd probabilities, not advice — how this works.