Best prediction market platform

Combined ranking

1. 1
   PPolymarket—19 pts

   GPT #2Claude #1Gemini #1Grok #1

   Deepest liquidity and tightest spreads of any prediction market by a wide margin, with the broadest event coverage (politics, geopolitics, crypto, sports, science) and a genuine order book on Polygon with no trading fees; its 2025 acquisition of CFTC-licensed QCEX opened a regulated path back to US users, removing its biggest historical caveat. Assumption: the typical practitioner wants real-money trading with enough depth to enter and exit meaningful positions.

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   Claude Deepest liquidity and tightest spreads of any prediction market by a wide margin, with the broadest event coverage (politics, geopolitics, crypto, sports, science) and a genuine order book on Polygon with no trading fees; its 2025 acquisition of CFTC-licensed QCEX opened a regulated path back to US users, removing its biggest historical caveat. Assumption: the typical practitioner wants real-money trading with enough depth to enter and exit meaningful positions.

   Gemini Delivers the deepest global order-book liquidity, near-zero trading fees on Polygon, and the broadest variety of real-time macroeconomic, political, and world event markets.

   Grok deepest liquidity, broadest event coverage (politics, crypto, sports, global news), self-custodial USDC on Polygon with fast execution, strong CFTC-regulated US arm, proven high-volume track record

   GPT Near-tied with Kalshi on trading merit and often stronger for global politics, geopolitics, market breadth, public on-chain data, and automation; deep liquidity and maker-friendly economics especially reward sophisticated users

   Where it falls short

   per GPT Geographic restrictions, USDC/crypto infrastructure, and jurisdiction-dependent regulatory risk make it less universally practical

   per Claude USDC/crypto-native onboarding and settlement still adds friction for non-crypto users, and resolution disputes via UMA's oracle have produced occasional contested outcomes on ambiguous markets.

   per Gemini Geoblocked for US residents and requires Web3 wallet onboarding, making it unsuitable for regulatory-bound US investors.

   per Grok crypto-native (volatility in collateral, wallet setup barrier for fiat-only users)

2. 2
   KKalshi—17 pts

   GPT #1Claude #2Gemini #2Grok #2

   Best all-around choice for typical U.S. traders: broad real-money event coverage, strong liquidity, clear contract rules, mature API and trading tools, and federal exchange oversight; ranked first assuming lawful availability in the user’s state

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   GPT Best all-around choice for typical U.S. traders: broad real-money event coverage, strong liquidity, clear contract rules, mature API and trading tools, and federal exchange oversight; ranked first assuming lawful availability in the user’s state

   Claude The only fully CFTC-regulated US exchange in the category — fiat deposits, brokerage-style compliance, 1099 tax reporting, and API access — with rapidly expanded coverage (economics, weather, politics, sports) after court wins cleared election and sports contracts; near-tie with Polymarket for a US practitioner who prioritizes regulatory safety over depth.

   Gemini Fully CFTC-regulated US exchange offering direct USD bank integration and legal compliance for US retail and institutional event contract trading. Near-tie with Polymarket for practitioners prioritizing US legal status over global market breadth.

   Grok fully CFTC-regulated fiat platform with strong US accessibility, high liquidity especially in regulated events/sports, user-friendly for beginners, reliable settlement and compliance

   Where it falls short

   per GPT Sports-contract access and legality still vary by state, and active-trader fees can materially erode small edges

   per Claude Liquidity on most non-headline markets is thin relative to Polymarket, so large positions move prices, and fee structure (per-contract trading fees) eats edge on low-margin trades.

   per Gemini Strict regulatory oversight slows market creation speed and restricts topic variety compared to decentralized competitors.

   per Grok more restricted market scope and slower innovation than crypto platforms, geographic limits outside US

3. 3
   PPredictIt—8 pts

   GPT #5Claude #5Gemini #3Grok #3

   Established liquidity and deep trader concentration specifically optimized for US federal, state, and legislative political outcomes.

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   Gemini Established liquidity and deep trader concentration specifically optimized for US federal, state, and legislative political outcomes.

   Grok established political focus with real-money trading, improved caps post-2025 regulatory wins, good for targeted election and policy forecasts with academic roots

   GPT Straightforward real-money political markets, readable rules, limit orders, and a long-running community make it useful for election specialists who value simplicity over breadth

   Claude The longest-running legal US political market, still operating under its academic no-action arrangement after surviving the CFTC's shutdown attempt, with a devoted user base and useful price history on US politics; earns the last spot on longevity and political-market focus, not on mechanics.

   Where it falls short

   per GPT Narrow political focus, restrictive position limits, and comparatively unfavorable fees constrain serious trading and price efficiency

   per Claude Structurally hobbled — $850 position caps per contract, 10% profit fee and 5% withdrawal fee, and politics-only scope make it strictly worse for serious sizing than Kalshi or Polymarket.

   per Gemini Imposes a strict $850 cap per position alongside high operational fees (10% profit fee and 5% withdrawal fee).

   per Grok lower overall liquidity and volume compared to leaders, narrower non-political coverage

4. 4
   MManifold—6 pts

   GPT #4Claude #4Gemini #4Grok —

   Best platform for creating custom markets, practicing forecasting, and running community or organizational questions without risking capital; free play money enables unusual, niche, and experimental markets

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   GPT Best platform for creating custom markets, practicing forecasting, and running community or organizational questions without risking capital; free play money enables unusual, niche, and experimental markets

   Claude Anyone can create a market in seconds with play-money (mana), producing unmatched question breadth and a lively community of calibrated forecasters; excellent for testing question designs, niche topics, and personal/organizational forecasting with an open API and free entry.

   Gemini Allows instant, permissionless creation of custom markets on any topic, providing unmatched coverage for niche events and rapid community feedback.

   Where it falls short

   per GPT Mana is not redeemable for cash, so prices lack the financial incentives and tradable value sought by real-money practitioners

   per Claude Play money plus user-created resolution means variable question quality and self-resolution disputes — signal on any single market is far noisier than on real-money venues.

   per Gemini Relies on play money (Mana) and sweepstakes models rather than deep real-money order books, limiting financial price discovery on high-stakes events.

5. 5
   MMetaculus—4 pts

   GPT —Claude #3Gemini #5Grok —

   The strongest platform for forecasting skill rather than trading — long-horizon and low-probability questions (AI, science, geopolitics) that money markets can't sustain, rigorous resolution criteria, track-record scoring, and an aggregate that has repeatedly matched or beaten market prices; ideal for practitioners whose goal is calibration and insight, not profit.

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   Claude The strongest platform for forecasting skill rather than trading — long-horizon and low-probability questions (AI, science, geopolitics) that money markets can't sustain, rigorous resolution criteria, track-record scoring, and an aggregate that has repeatedly matched or beaten market prices; ideal for practitioners whose goal is calibration and insight, not profit.

   Gemini Recognized leader for structured quantitative forecasting, track-record calibration, and high-quality aggregate reasoning on complex long-term scientific and geopolitical questions.

   Where it falls short

   per Claude No real-money stakes, so no way to monetize edge and weaker incentives against herding; it's a reputation-based forecasting site, not a market.

   per Gemini Operates as a reputation-scored forecasting platform rather than a financial exchange with cash liquidity and order-book execution.

6. 6
   IInteractive Brokers ForecastTrader—3 pts

   GPT #3Claude —Gemini —Grok —

   ForecastEx contracts inside a serious multi-asset brokerage provide regulated access, portfolio integration, advanced order tools, low per-contract commissions, and interest-like incentives on contract value

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   GPT ForecastEx contracts inside a serious multi-asset brokerage provide regulated access, portfolio integration, advanced order tools, low per-contract commissions, and interest-like incentives on contract value

   Where it falls short

   per GPT Its event catalog and liquidity are substantially thinner than the two leaders, so many questions are unavailable or costly to trade at size

Just missed the top 5

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Tracked by ModelsAgree · rank 1 = 5 pts … rank 5 = 1 pt · re-polled weekly