Anthropic’s recent launch of Claude Fable 5.1 and Mythos 5.1 on September 1 has reinforced its lead on independent leaderboards measuring coding, reasoning, and knowledge-work benchmarks, driving the 79.5% market-implied probability for the company to hold the top Arena score (style control on) at month-end. Multiple aggregators currently rank these models ahead of OpenAI’s GPT-5.6 variants and others, reflecting sustained gains in agentic capabilities and efficiency since earlier 2026 releases like Opus 5 and Sonnet 5. Traders see limited near-term disruption from competitors, though any late-September OpenAI update or Arena volatility could still shift the snapshot before resolution.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedAnthropic 80%
OpenAI 12.8%
Meta 3.6%
Google 1.9%
$89,281 Vol.
$89,281 Vol.
Sep 30, 2026
Anthropic
80%
OpenAI
13%
Meta
4%
2%
Alibaba
1%
Moonshot
<1%
Z.ai
<1%
SpaceXAI
<1%
Baidu
<1%
Xiaomi
<1%
DeepSeek
<1%
ByteDance
<1%
MiniMax
<1%
Thinky
<1%
Meituan
<1%
Mistral
<1%
Amazon
<1%
Nvidia
<1%
Tencent
<1%
StepFun
<1%
Microsoft
<1%
Anthropic 80%
OpenAI 12.8%
Meta 3.6%
Google 1.9%
$89,281 Vol.
$89,281 Vol.
Sep 30, 2026
Anthropic
$39,799 Vol.
80%
OpenAI
$8,831 Vol.
13%
Meta
$7,909 Vol.
4%
$5,713 Vol.
2%
Alibaba
$3,844 Vol.
1%
Moonshot
$3,212 Vol.
<1%
Z.ai
$2,870 Vol.
<1%
SpaceXAI
$2,852 Vol.
<1%
Baidu
$769 Vol.
<1%
Xiaomi
$1,250 Vol.
<1%
DeepSeek
$1,431 Vol.
<1%
ByteDance
$436 Vol.
<1%
MiniMax
$436 Vol.
<1%
Thinky
$1,313 Vol.
<1%
Meituan
$930 Vol.
<1%
Mistral
$1,554 Vol.
<1%
Amazon
$436 Vol.
<1%
Nvidia
$920 Vol.
<1%
Tencent
$2,658 Vol.
<1%
StepFun
$1,360 Vol.
<1%
Microsoft
$762 Vol.
<1%
This market will resolve according to the company which owns the model which has the highest arena rank based on the arena.ai Text Arena (Overall) (Style Control On) when the table under the "Leaderboard" tab is checked on September 30, 2026, 12:00 PM ET.
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall with style control on (Adjustments: Style Control) and filtered for "Models" will be used to resolve this market.
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 company names as listed in this market group will be used as a final tiebreaker (e.g., if the two models are tied by exact arena score, “Google” would be ranked ahead of “SpaceXAI”). This market will resolve based on the company that occupies first place under this ranking.
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".Anthropic’s recent launch of Claude Fable 5.1 and Mythos 5.1 on September 1 has reinforced its lead on independent leaderboards measuring coding, reasoning, and knowledge-work benchmarks, driving the 79.5% market-implied probability for the company to hold the top Arena score (style control on) at month-end. Multiple aggregators currently rank these models ahead of OpenAI’s GPT-5.6 variants and others, reflecting sustained gains in agentic capabilities and efficiency since earlier 2026 releases like Opus 5 and Sonnet 5. Traders see limited near-term disruption from competitors, though any late-September OpenAI update or Arena volatility could still shift the snapshot before resolution.
This market will resolve according to the company which owns the model which has the highest arena rank based on the arena.ai Text Arena (Overall) (Style Control On) when the table under the "Leaderboard" tab is checked on September 30, 2026, 12:00 PM ET.
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall with style control on (Adjustments: Style Control) and filtered for "Models" will be used to resolve this market.
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 company names as listed in this market group will be used as a final tiebreaker (e.g., if the two models are tied by exact arena score, “Google” would be ranked ahead of “SpaceXAI”). This market will resolve based on the company that occupies first place under this ranking.
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 with style control on (Adjustments: Style Control) and filtered for "Models" will be used to resolve this market.
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 company names as listed in this market group will be used as a final tiebreaker (e.g., if the two models are tied by exact arena score, “Google” would be ranked ahead of “SpaceXAI”). This market will resolve based on the company that occupies first place under this ranking.
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: Jul 20, 2026, 8:32 PM ET
Volume
$89,281End Date
Oct 1, 2026Market Opened
Jul 20, 2026, 8:32 PM ETResolution Source
https://arena.ai/leaderboard/text/overallResolver
0x69c47De9D...This market will resolve according to the company which owns the model which has the highest arena rank based on the arena.ai Text Arena (Overall) (Style Control On) when the table under the "Leaderboard" tab is checked on September 30, 2026, 12:00 PM ET.
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall with style control on (Adjustments: Style Control) and filtered for "Models" will be used to resolve this market.
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 company names as listed in this market group will be used as a final tiebreaker (e.g., if the two models are tied by exact arena score, “Google” would be ranked ahead of “SpaceXAI”). This market will resolve based on the company that occupies first place under this ranking.
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".Anthropic’s recent launch of Claude Fable 5.1 and Mythos 5.1 on September 1 has reinforced its lead on independent leaderboards measuring coding, reasoning, and knowledge-work benchmarks, driving the 79.5% market-implied probability for the company to hold the top Arena score (style control on) at month-end. Multiple aggregators currently rank these models ahead of OpenAI’s GPT-5.6 variants and others, reflecting sustained gains in agentic capabilities and efficiency since earlier 2026 releases like Opus 5 and Sonnet 5. Traders see limited near-term disruption from competitors, though any late-September OpenAI update or Arena volatility could still shift the snapshot before resolution.
This market will resolve according to the company which owns the model which has the highest arena rank based on the arena.ai Text Arena (Overall) (Style Control On) when the table under the "Leaderboard" tab is checked on September 30, 2026, 12:00 PM ET.
Results from the "Rank" column under the "Text Arena | Overall" Leaderboard tab at https://arena.ai/leaderboard/text/overall with style control on (Adjustments: Style Control) and filtered for "Models" will be used to resolve this market.
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 company names as listed in this market group will be used as a final tiebreaker (e.g., if the two models are tied by exact arena score, “Google” would be ranked ahead of “SpaceXAI”). This market will resolve based on the company that occupies first place under this ranking.
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 with style control on (Adjustments: Style Control) and filtered for "Models" will be used to resolve this market.
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 company names as listed in this market group will be used as a final tiebreaker (e.g., if the two models are tied by exact arena score, “Google” would be ranked ahead of “SpaceXAI”). This market will resolve based on the company that occupies first place under this ranking.
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
$89,281End Date
Oct 1, 2026Market Opened
Jul 20, 2026, 8:32 PM ETResolution Source
https://arena.ai/leaderboard/text/overallResolver
0x69c47De9D...Anthropic’s recent launch of Claude Fable 5.1 and Mythos 5.1 on September 1 has reinforced its lead on independent leaderboards measuring coding, reasoning, and knowledge-work benchmarks, driving the 79.5% market-implied probability for the company to hold the top Arena score (style control on) at month-end. Multiple aggregators currently rank these models ahead of OpenAI’s GPT-5.6 variants and others, reflecting sustained gains in agentic capabilities and efficiency since earlier 2026 releases like Opus 5 and Sonnet 5. Traders see limited near-term disruption from competitors, though any late-September OpenAI update or Arena volatility could still shift the snapshot before resolution.
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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