**Claude Fable 5.1 Max leads the September 14 “best AI model” market at 63.5% implied probability following its September 1 release.** Anthropic positioned the update as its strongest model for long-horizon agentic coding, multistep research, and document workflows, with a 1M-token context window, adaptive thinking, and meaningful gains on benchmarks such as SWE-bench Verified and Frontier-Bench over the prior Fable 5. The model’s improved efficiency at lower effort settings and reduced cache-read pricing have reinforced trader expectations that it will top independent leaderboards by mid-month. Earlier Opus 5 and Opus 4.x variants trail at low single-digit odds, reflecting their established but comparatively lower capability tier. The 32.5% “Other” share leaves room for a surprise challenger release, though no competing frontier model has shipped in the past week.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updatedclaude-fable-5.1-max 64%
Other 33%
claude-opus-5-max 2.2%
claude-opus-5-high 1.7%
NEW
NEW
Sep 14, 2026
claude-fable-5.1-max
64%
Other
33%
claude-opus-5-max
2%
claude-opus-5-high
2%
claude-opus-4-6-high
1%
claude-fable-5.1-max 64%
Other 33%
claude-opus-5-max 2.2%
claude-opus-5-high 1.7%
NEW
NEW
Sep 14, 2026
claude-fable-5.1-max
$4,211 Vol.
64%
Other
$5,042 Vol.
33%
claude-opus-5-max
$148 Vol.
2%
claude-opus-5-high
$146 Vol.
2%
claude-opus-4-6-high
$255 Vol.
1%
This market will resolve according to the model that has the highest arena rank based on the arena.ai Text Arena (Overall) when the table under the "Leaderboard" tab is checked on the specified date, 12:00 PM ET.
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall-no-style-control with style control off (Adjustments: None) and filtered for "Models" will be used to resolve this market.
Note: Models marked “AutoEval” at the applicable check time will not be considered, regardless of whether they display a rank or score.
No new model will be added to this market after market creation. Any model not explicitly listed in this market will be encompassed under the "Other" option.
Models will be ordered primarily by their leaderboard rank at the market’s check time. If two or more models are tied on rank, they will be ordered by their Arena score, including any underlying, unrounded, granular values reflected in the data below the leaderboard. If a tie still remains, alphabetical order of model names as listed in this market group (full string, including suffixes such as “-high” and “-max”) will be used as a final tiebreaker (e.g., if two models remain tied, “claude-opus-5-high” would be ranked ahead of “claude-opus-5-max”). This market will resolve to the model that comes first according to this order.
The resolution source for this market is the arena.ai Text Arena (Overall). If this resolution source is unavailable at check time, this market will remain open until the leaderboard comes back online and will resolve based on the first check after it becomes available. If it becomes permanently unavailable, this market will resolve to "Other".**Claude Fable 5.1 Max leads the September 14 “best AI model” market at 63.5% implied probability following its September 1 release.** Anthropic positioned the update as its strongest model for long-horizon agentic coding, multistep research, and document workflows, with a 1M-token context window, adaptive thinking, and meaningful gains on benchmarks such as SWE-bench Verified and Frontier-Bench over the prior Fable 5. The model’s improved efficiency at lower effort settings and reduced cache-read pricing have reinforced trader expectations that it will top independent leaderboards by mid-month. Earlier Opus 5 and Opus 4.x variants trail at low single-digit odds, reflecting their established but comparatively lower capability tier. The 32.5% “Other” share leaves room for a surprise challenger release, though no competing frontier model has shipped in the past week.
This market will resolve according to the model that has the highest arena rank based on the arena.ai Text Arena (Overall) when the table under the "Leaderboard" tab is checked on the specified date, 12:00 PM ET.
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall-no-style-control with style control off (Adjustments: None) and filtered for "Models" will be used to resolve this market.
Note: Models marked “AutoEval” at the applicable check time will not be considered, regardless of whether they display a rank or score.
No new model will be added to this market after market creation. Any model not explicitly listed in this market will be encompassed under the "Other" option.
Models will be ordered primarily by their leaderboard rank at the market’s check time. If two or more models are tied on rank, they will be ordered by their Arena score, including any underlying, unrounded, granular values reflected in the data below the leaderboard. If a tie still remains, alphabetical order of model names as listed in this market group (full string, including suffixes such as “-high” and “-max”) will be used as a final tiebreaker (e.g., if two models remain tied, “claude-opus-5-high” would be ranked ahead of “claude-opus-5-max”). This market will resolve to the model that comes first according to this order.
The resolution source for this market is the arena.ai Text Arena (Overall). If this resolution source is unavailable at check time, this market will remain open until the leaderboard comes back online and will resolve based on the first check after it becomes available. If it becomes permanently unavailable, this market will resolve to "Other".
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall-no-style-control with style control off (Adjustments: None) and filtered for "Models" will be used to resolve this market.
Note: Models marked “AutoEval” at the applicable check time will not be considered, regardless of whether they display a rank or score.
No new model will be added to this market after market creation. Any model not explicitly listed in this market will be encompassed under the "Other" option.
Models will be ordered primarily by their leaderboard rank at the market’s check time. If two or more models are tied on rank, they will be ordered by their Arena score, including any underlying, unrounded, granular values reflected in the data below the leaderboard. If a tie still remains, alphabetical order of model names as listed in this market group (full string, including suffixes such as “-high” and “-max”) will be used as a final tiebreaker (e.g., if two models remain tied, “claude-opus-5-high” would be ranked ahead of “claude-opus-5-max”). This market will resolve to the model that comes first according to this order.
The resolution source for this market is the arena.ai Text Arena (Overall). If this resolution source is unavailable at check time, this market will remain open until the leaderboard comes back online and will resolve based on the first check after it becomes available. If it becomes permanently unavailable, this market will resolve to "Other".
Market Opened: Sep 3, 2026, 10:16 AM ET
Volume
$9,801End Date
Sep 14, 2026Market Opened
Sep 3, 2026, 10:16 AM ETResolution Source
https://arena.ai/leaderboard/text/overall-no-style-controlResolver
0x69c47De9D...This market will resolve according to the model that has the highest arena rank based on the arena.ai Text Arena (Overall) when the table under the "Leaderboard" tab is checked on the specified date, 12:00 PM ET.
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall-no-style-control with style control off (Adjustments: None) and filtered for "Models" will be used to resolve this market.
Note: Models marked “AutoEval” at the applicable check time will not be considered, regardless of whether they display a rank or score.
No new model will be added to this market after market creation. Any model not explicitly listed in this market will be encompassed under the "Other" option.
Models will be ordered primarily by their leaderboard rank at the market’s check time. If two or more models are tied on rank, they will be ordered by their Arena score, including any underlying, unrounded, granular values reflected in the data below the leaderboard. If a tie still remains, alphabetical order of model names as listed in this market group (full string, including suffixes such as “-high” and “-max”) will be used as a final tiebreaker (e.g., if two models remain tied, “claude-opus-5-high” would be ranked ahead of “claude-opus-5-max”). This market will resolve to the model that comes first according to this order.
The resolution source for this market is the arena.ai Text Arena (Overall). If this resolution source is unavailable at check time, this market will remain open until the leaderboard comes back online and will resolve based on the first check after it becomes available. If it becomes permanently unavailable, this market will resolve to "Other".**Claude Fable 5.1 Max leads the September 14 “best AI model” market at 63.5% implied probability following its September 1 release.** Anthropic positioned the update as its strongest model for long-horizon agentic coding, multistep research, and document workflows, with a 1M-token context window, adaptive thinking, and meaningful gains on benchmarks such as SWE-bench Verified and Frontier-Bench over the prior Fable 5. The model’s improved efficiency at lower effort settings and reduced cache-read pricing have reinforced trader expectations that it will top independent leaderboards by mid-month. Earlier Opus 5 and Opus 4.x variants trail at low single-digit odds, reflecting their established but comparatively lower capability tier. The 32.5% “Other” share leaves room for a surprise challenger release, though no competing frontier model has shipped in the past week.
This market will resolve according to the model that has the highest arena rank based on the arena.ai Text Arena (Overall) when the table under the "Leaderboard" tab is checked on the specified date, 12:00 PM ET.
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall-no-style-control with style control off (Adjustments: None) and filtered for "Models" will be used to resolve this market.
Note: Models marked “AutoEval” at the applicable check time will not be considered, regardless of whether they display a rank or score.
No new model will be added to this market after market creation. Any model not explicitly listed in this market will be encompassed under the "Other" option.
Models will be ordered primarily by their leaderboard rank at the market’s check time. If two or more models are tied on rank, they will be ordered by their Arena score, including any underlying, unrounded, granular values reflected in the data below the leaderboard. If a tie still remains, alphabetical order of model names as listed in this market group (full string, including suffixes such as “-high” and “-max”) will be used as a final tiebreaker (e.g., if two models remain tied, “claude-opus-5-high” would be ranked ahead of “claude-opus-5-max”). This market will resolve to the model that comes first according to this order.
The resolution source for this market is the arena.ai Text Arena (Overall). If this resolution source is unavailable at check time, this market will remain open until the leaderboard comes back online and will resolve based on the first check after it becomes available. If it becomes permanently unavailable, this market will resolve to "Other".
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall-no-style-control with style control off (Adjustments: None) and filtered for "Models" will be used to resolve this market.
Note: Models marked “AutoEval” at the applicable check time will not be considered, regardless of whether they display a rank or score.
No new model will be added to this market after market creation. Any model not explicitly listed in this market will be encompassed under the "Other" option.
Models will be ordered primarily by their leaderboard rank at the market’s check time. If two or more models are tied on rank, they will be ordered by their Arena score, including any underlying, unrounded, granular values reflected in the data below the leaderboard. If a tie still remains, alphabetical order of model names as listed in this market group (full string, including suffixes such as “-high” and “-max”) will be used as a final tiebreaker (e.g., if two models remain tied, “claude-opus-5-high” would be ranked ahead of “claude-opus-5-max”). This market will resolve to the model that comes first according to this order.
The resolution source for this market is the arena.ai Text Arena (Overall). If this resolution source is unavailable at check time, this market will remain open until the leaderboard comes back online and will resolve based on the first check after it becomes available. If it becomes permanently unavailable, this market will resolve to "Other".
Volume
$9,801End Date
Sep 14, 2026Market Opened
Sep 3, 2026, 10:16 AM ETResolution Source
https://arena.ai/leaderboard/text/overall-no-style-controlResolver
0x69c47De9D...**Claude Fable 5.1 Max leads the September 14 “best AI model” market at 63.5% implied probability following its September 1 release.** Anthropic positioned the update as its strongest model for long-horizon agentic coding, multistep research, and document workflows, with a 1M-token context window, adaptive thinking, and meaningful gains on benchmarks such as SWE-bench Verified and Frontier-Bench over the prior Fable 5. The model’s improved efficiency at lower effort settings and reduced cache-read pricing have reinforced trader expectations that it will top independent leaderboards by mid-month. Earlier Opus 5 and Opus 4.x variants trail at low single-digit odds, reflecting their established but comparatively lower capability tier. The 32.5% “Other” share leaves room for a surprise challenger release, though no competing frontier model has shipped in the past week.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated
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