Next Mythos-Class Model release date
Odds summary
September 30 currently leads the Next Mythos-Class Model release date prediction market at 71% reported probability on Polymarket. The figures below combine live odds, liquidity, volume, and open interest so readers can compare the market signal before reading the full analysis.
Odds, liquidity, volume, and open interest are sourced from Polymarket and last synced at Aug 13, 2026 1:12 pm.
Anthropic’s Access Controls Shape the Late Mythos Release Curve
The steep jump after July points to a market-implied sequence in which regulatory clearance and partner access precede another qualifying release. That reading depends on an unresolved distinction between a new model, a wider rollout, and the June 9 launch already cited in the rules.

The deadline hierarchy suggests that Anthropic’s access policy has become the market’s timing signal for another Mythos-class release. The key inference is that regulatory approval and controlled partner deployment could produce a qualifying announcement during August or September, while the existing model’s restricted status makes an immediate follow-on release difficult to establish.
The curve concentrates the release window in August
July 31 trades at 0.9%, compared with 43% for August 31 and 72.5% for September 30. Assuming these binaries are interpreted cumulatively, the 42.1-point jump into August identifies that month as the first meaningful window. September contributes another 29.5 points, while the remaining 27.5 points represent scenarios in which no qualifying release occurs by the final deadline.
This distribution fits a staged process: access restrictions ease, trusted organizations test the system, and Anthropic then announces either a successor or a newly available Mythos-class product. That sequence is a market inference. Anthropic has disclosed partner expansion and access changes, though it has not supplied a release schedule for another model in the provided record.
The June launch makes model definition the hidden variable
Anthropic publicly launched Claude Fable 5 on June 9, describing it as a Mythos-class model made safe for general use. It also said Claude Mythos 5 uses the same underlying model, with cyber safeguards lifted, and initially limited Mythos 5 to vetted partners. Those facts establish Anthropic’s ownership of the category while complicating what constitutes the “next” release.
The resolution criteria explicitly cite the June 9 Fable 5 release. The deadline prices therefore rely on an implicit assumption that settlement requires a subsequent event. The supplied rules do not specify whether expanded access, a renamed configuration, or a new underlying model would qualify. A formal resolution clarification could change the entire curve because every listed deadline falls after the cited launch.
Restrictions separate rollout timing from model creation
On June 12, Anthropic said a U.S. government directive required it to suspend Fable 5 and Mythos 5 access for foreign nationals, leading the company to disable access for all customers. Anthropic later said Mythos 5 export controls were lifted on July 1 and access was restored for a set of U.S. organizations.
This sequence supports the late-window thesis by showing that distribution can change within weeks of a policy decision. Broader authorization could create the conditions for a public product announcement. It does not establish that a separate model is ready. Regulatory progress therefore confirms the access component of the thesis while providing limited evidence about a successor’s development schedule.
Specific announcements would define the August-September thesis
The strongest hypothetical repricing catalysts would resolve either timing or definition:
- An Anthropic announcement explicitly describing a new system as Mythos-class and providing a release date.
- A new transparency-hub entry with a distinct model name, system documentation, or knowledge cutoff.
- A broader government authorization followed by availability outside the current trusted-access group.
- Resolver guidance stating whether partner access expansions qualify as releases.
The opposite evidence would include renewed government restrictions, Anthropic continuing to identify Fable 5 and Mythos 5 as its only Mythos-class offerings, or a rules clarification requiring a genuinely new underlying model. Each would weaken the inferred link between access restoration and a near-term qualifying release.
Anthropic’s own taxonomy provides the strongest counter-signal
Anthropic says Fable 5 and Mythos 5 are the same underlying model. Its transparency hub gives Mythos 5 a January 2026 knowledge cutoff and describes availability as limited to selected partners for defensive cybersecurity and biological purposes. This supports a slower interpretation: Fable and Mythos may represent safeguard and access configurations within one generation, leaving another qualifying release dependent on a genuinely new model.
Project Glasswing’s expansion to roughly 150 organizations across more than fifteen countries before the June launch shows an established partner pipeline. It can support further deployment announcements, though deployment alone may fail the market’s release test. With $80.56K in volume, $25.57K in open interest, and $14.16K in liquidity, a definitive Anthropic statement or resolution ruling could produce a substantial adjustment relative to available liquidity.
Sources
What could move the odds?
Informational summary of factors that may affect the reported prediction-market probabilities.
Market-implied thesis
The price curve implies a follow-on Mythos-class release is more likely than not by late September, but not clearly by mid-month.
Because the first public Mythos-class model arrived on June 9, the market is pricing a second qualifying release rather than the already-released Claude Fable 5.
What could reprice it
Anthropic’s September 15 Phase 1 completion target is the clearest dated decision-gate that could shift expectations for a September release.
The Frontier Safety Roadmap also sets a September 30 prototype target. Evidence of completion, slippage, or a changed sequencing link to releases could materially alter the timing thesis.
Where the market may be weak
The rules do not clearly define what constitutes the “next” Mythos-class release or identify a definitive resolution source, leaving classification risk.
The stated criterion identifies the June 9 Fable 5 launch, while the question concerns a subsequent release. That gap matters if Anthropic redeploys, renames, limits access to, or safeguards a model.
Counter-signal
The U.S. export-control directive restricting Fable 5 and Mythos 5 access is the strongest reason a near-term follow-on launch could be delayed or narrowed.
Anthropic said on June 12 that access was suspended for foreign nationals, including foreign-national employees. Restricted deployment and testing can disrupt the development and release path implied by a short cadence.
Market details
- Resolution criteria
- On June 9, 2026, Anthropic released the Mythos-class model Claude Fable 5.
- Category
- Tech › AI
- Close date
- September 30, 2026, 12:00 AM UTC
- Market rules summary
- Multi-timeframe Polymarket event. Each listed timeframe is represented by its Yes price on the underlying binary market. View full rules
Frequently asked questions
What are the current Next Mythos-Class Model release date odds?
Polymarket reports Next Mythos-Class Model release date odds with September 30 at 71%, September 15 at 45%, and August 31 at 20.5%. These probabilities are market-implied and can change as liquidity and trading activity update. The latest market snapshot includes $107.46K volume, $5.74K liquidity, and $26.89K open interest. CryptoSlate last synced this market data at Aug 13, 2026, 12:12 UTC.
What could move the Next Mythos-Class Model release date prediction market odds?
The price curve implies a follow-on Mythos-class release is more likely than not by late September, but not clearly by mid-month. Because the first public Mythos-class model arrived on June 9, the market is pricing a second qualifying release rather than the already-released Claude Fable 5. Catalysts to watch include Anthropic’s September 15 Phase 1 safety-roadmap completion target., September 15, 2026 Phase 1 completion target., and A disputed model classification or access status..
How does the Next Mythos-Class Model release date prediction market resolve?
On June 9, 2026, Anthropic released the Mythos-class model Claude Fable 5. Multi-timeframe Polymarket event. Each listed timeframe is represented by its Yes price on the underlying binary market.