Will Anthropic have the best AI model at the end of September 2026?

ResolutionResolved YES

YES payout100¢

NO payout0¢

VenuePolymarket

Realized · held to resolution+22%$100 paper stake

Polymarket82¢ → 100¢

Our position · YES82¢ → 100¢

Signal endedSep 30

Forecast updated

Sep 6 forecast

Anthropic occupied the top five Text Arena spots in the latest resolution-source snapshot, so an Anthropic model leading at September’s end is highly likely.

Anthropic held every top-five position in the September 2 Text Arena Overall snapshot, giving it several ways to retain the company lead. Independent evaluations published after GPT-6 Astra’s release also continued to place Claude Fable 5.1 ahead. OpenAI’s new model, recent Google and Meta releases, and variation between same-day Arena records create meaningful uncertainty, but a rival must still displace Anthropic’s unusually broad presence at the top. An Anthropic model leading at September’s end is therefore highly likely.

Points to YES

Anthropic controls several leading positions rather than relying on one model.
On September 2, the Text Arena Overall snapshot ranked Claude Fable 5.1 Max first and placed Anthropic models in all five top positions.
Independent comparisons still favor Claude after the newest major rival releases.
On September 6, Artificial Analysis ranked Claude Fable 5.1 first, Claude Opus 5 second, and GPT-6 Astra fifth.

Points to NO

GPT-6 Astra gives OpenAI a fresh and potentially fast-moving challenger.
OpenAI released GPT-6 Astra on September 3 and made it available through its API and several paid user tiers.
The exact ordering of Anthropic’s leading models is not fully stable across supplied Arena records.
Two records displaying September 2 Arena data placed Claude Fable 5.1 Max first in one record and third in another, although both had an Anthropic model first.

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