Polymarket vs Kalshi (2026): Fees, Liquidity, Regulation

Looking to trade on prediction markets? Here's what you need to know about Polymarket and Kalshi, from Polymarket's return to the U.S. to running a bot on a Kalshi VPS.

Polymarket and Kalshi are two leading platforms for event-based trading, but they cater to different user needs. Polymarket is a crypto-based platform with global reach, while Kalshi operates under U.S. regulations, offering fiat trading and federal protections.

Key differences include:

• Liquidity: Polymarket leads in global politics and crypto markets, while Kalshi dominates U.S. sports and economic events, often driven by market making in prediction markets to maintain order book depth.
• Fees: Both charge taker fees that peak at a 50¢ price: $1.00 to $1.75 per 100 contracts on international Polymarket, depending on the market category (geopolitics markets are free), and $1.75 on most Kalshi markets (checked on 10 Oct 2026).
• Regulation: Kalshi is fully CFTC-regulated with FDIC-insured USD accounts, whereas Polymarket operates both offshore and U.S.-regulated versions.
• Withdrawals: Polymarket offers instant USDC withdrawals, while Kalshi relies on slower ACH transfers but compensates with a 3.50% variable APY on cash and open positions.

Quick Comparison Table:

Both platforms have strengths, but your choice depends on your trading goals. Polymarket is ideal for crypto-savvy, high-frequency traders, while Kalshi suits those prioritizing regulatory certainty and fiat convenience.

Liquidity and Market Depth Comparison

As of February 2026, Kalshi holds a slight lead in weekly trading volume, handling about $2.7 billion each week (53% market share). In comparison, Polymarket International processes around $2.1 billion weekly, accounting for 47% of the market share. However, each platform shines in different areas, catering to distinct market segments. Let’s break down how these differences influence trading strategies and liquidity.

Polymarket dominates in markets related to politics, geopolitics, and cryptocurrencies. Its wider range of offerings and global, crypto-savvy user base give it an edge, especially for international events. On the other hand, Kalshi leads the charge in sports-related markets, particularly during the 2025–26 season, with 90% of its total volume coming from NFL, NBA, and MLB contracts.

For liquidity, traders encounter notable differences in order book depth and spreads. Polymarket typically offers tighter spreads, ranging from 2–5 cents, while Kalshi’s spreads are wider, averaging 3–8 cents. Additionally, Polymarket’s market depth is more resistant to price shifts - it takes approximately 3.5 times more trading volume to move the market on Polymarket than on Kalshi. For instance, placing a 5,000-contract order results in 1–2% slippage on Polymarket, compared to 2–4% slippage on Kalshi.

"Polymarket requires roughly 3–4× more notional volume to generate a comparable price move over a 60-second horizon." – Pantera Research Lab

Another factor influencing platform choice is the speed of capital movement. Polymarket offers near-instant USDC withdrawals on-chain, making it appealing for crypto users. In contrast, Kalshi relies on ACH transfers, which take 1 to 3 business days. To offset this slower withdrawal process, Kalshi pays a variable 3.50% APY on cash and open positions for balances of $250 or more (checked on 10 Oct 2026). However, traders should also consider the cost of wider spreads: a 3-cent wider spread on a $1,000 position adds an extra $30 in costs.

These differences in liquidity, trading costs, and withdrawal options highlight how each platform caters to specific trader preferences and strategies.

Regulatory Framework and Compliance

Polymarket and Kalshi operate under distinct structures and timelines, with differing levels of federal oversight. Kalshi functions as a Designated Contract Market (DCM), a status granted by the Commodity Futures Trading Commission (CFTC) in November 2020. This designation allows Kalshi to offer event contracts as regulated derivatives under the Commodity Exchange Act (CEA), distinguishing them from gambling products. Polymarket, on the other hand, operates two versions: Polymarket International (offshore and decentralized, blocking U.S. users) and Polymarket US (relaunched in beta in 2025 after acquiring QCEX, a CFTC-licensed exchange, for $112 million). However, Polymarket International faced a $1.4 million fine from the CFTC in 2022 for running an unregistered facility. Despite these frameworks, both platforms are navigating complex legal challenges tied to federal and state regulations.

A major legal hurdle emerged in 2026: the clash between federal CFTC authority and state gaming laws. Courts in Nevada and the 9th Circuit ruled in early 2026 that state gaming regulators could independently enforce laws against these platforms, particularly for sports-related contracts. Specifically, the 9th Circuit ruled on February 18, followed by a federal court on March 3, that state gaming regulators could intervene, impacting Kalshi's sports contracts and sending Polymarket's case back to Nevada state court. As of March 2026, Kalshi is facing enforcement actions or legal challenges in around 24 states. These legal battles have far-reaching effects on their operations, highlighting the contrasting compliance demands of each platform.

"The tension between federal CFTC authority and state gaming regulation is 100% going to the Supreme Court." – Caroline Pham, Former Interim CFTC Chair

The platforms also differ in how they handle compliance. Kalshi mandates full KYC (identity verification) and operates exclusively in USD, while Polymarket US requires KYC (including SSN, with an ID check if needed) and trades in U.S. dollars. Kalshi offers FDIC insurance up to $250,000 for user funds and provides standard tax forms (1099-INT, 1099-MISC, 1099-B). In contrast, Polymarket US is still developing its tax reporting infrastructure. Both platforms are restricted by CFTC Regulation 40.11, which prohibits contracts related to war, terrorism, or assassination. For instance, Kalshi halted its "Khamenei" market in February 2026 due to this rule, while Polymarket International (offshore) allowed it to resolve.

These regulatory differences directly affect user accessibility and trust. Kalshi is available in most states, though sports-related markets are geofenced in Nevada. Meanwhile, Polymarket US is live as a CFTC-regulated exchange for U.S. users who pass identity verification in its app, while the international platform is close-only for U.S. users. CFTC Chairman Michael Selig has defended prediction markets as serving a "price discovery function" and emphasized the CFTC's "exclusive jurisdiction" over event contracts on regulated exchanges. However, state courts are increasingly challenging this interpretation, further complicating the regulatory environment.

Trading Strategies and Use Cases

The differences in liquidity and regulations between platforms also shape the trading strategies they support, highlighting their individual strengths. Fees on both platforms follow the same curve: they are highest at a 50¢ price and fall toward 1¢ and 99¢. A 100-contract taker order at 50¢ costs $1.00 to $1.75 on international Polymarket, depending on the market category, $1.74 on Polymarket US and $1.75 on most Kalshi markets (checked on 10 Oct 2026). For active traders, Polymarket's fee-free geopolitics markets and its maker rebates matter more than the headline rate.

Cross-platform arbitrage is another opportunity, capitalizing on brief price gaps between the platforms. These gaps typically last only 2–7 seconds. However, this strategy requires pre-funding accounts on both platforms, as Kalshi's slower ACH withdrawal process can pose challenges. While pure arbitrage opportunities occur around 5–15 times daily, they are mostly dominated by ultra-fast automated systems.

Traders can also benefit from market data in distinct ways. Whale tracking, for instance, is a feature unique to Polymarket due to its on-chain transparency. Tools like PolyMonit and Ratio allow users to track wallets making large trades ($10,000 or more) and instantly replicate those trades with a copy trading bot. This isn’t possible on Kalshi, which operates a closed system. Similarly, market making is more advantageous on Polymarket, where makers pay no fees and the international platform shares taker fees with makers as daily pUSD rebates. In contrast, Kalshi charges maker fees on some series, such as combos at 50% of the taker fee, which cut into profits on thin edges.

For macro hedging and institutional strategies, Kalshi is the platform of choice. Its CFTC regulation, FDIC-insured accounts (up to $250,000), and focus on economic indicators like Federal Reserve decisions and CPI data make it attractive to institutional traders. Additionally, Kalshi pays a variable 3.50% APY on cash and open positions (balances of $250 or more), which can help offset fees for traders with lower volumes. News-based trading also varies between platforms. Polymarket processes global news faster, about 3 to 7 seconds ahead of Kalshi, except for Federal Reserve-related events, where Kalshi’s institutional-grade data feeds provide a 2 to 4 second edge.

To optimize trading on either platform, limit orders are essential to control entry prices and avoid spread costs. This is especially true on Kalshi, where spreads can widen to 2–3% on secondary contracts, compared to Polymarket’s average spread of 1.2%. For larger trades, ensure there’s at least $50,000 in order book depth to minimize slippage. Finally, always verify the resolution rules for each market. Even if two markets appear identical, their outcomes can differ significantly depending on the platform’s specific rules.

These strategies reflect how liquidity and regulations shape the trading environment on each platform, offering unique opportunities for traders to explore.

API and Hosting for Bot Traders

Both platforms offer REST and WebSocket APIs for bots, but they sign requests differently and set different rate limits. Polymarket also runs two separate APIs: one for the international platform and one for Polymarket US.

Rate limits and auth checked on docs.polymarket.com, docs.polymarket.us and docs.kalshi.com on 10 Oct 2026. A Polymarket VPS in Dublin suits bots on the international order book.

Pros and Cons

Each platform offers a distinct set of advantages and drawbacks, shaped by differences in liquidity, fees, and regulatory frameworks:

Polymarket offers no maker fees, fee-free geopolitics markets and an ability to create markets within hours. It excels in providing liquidity and spreads for global politics and cryptocurrency markets, making it appealing for high-frequency traders. However, there are trade-offs: U.S. users must use the separate Polymarket US app, it doesn't pay interest on idle balances, and its reliance on cryptocurrency and USDC might not appeal to traditional traders.

Kalshi, on the other hand, benefits from its CFTC regulation and FDIC-insured accounts, which can reassure more cautious traders. Its fiat onboarding, enabled through ACH and bank transfers, simplifies the process for those unfamiliar with cryptocurrency. Additionally, it pays a variable 3.50% APY on balances of $250 or more, helping offset trading costs for users with lower volumes. Yet, Kalshi’s maker fees on some series, slower market creation due to regulatory reviews, and reduced liquidity in niche markets could be seen as limitations.

Here’s a side-by-side comparison of key features:

These distinctions highlight how each platform caters to different trading needs. Polymarket is better suited for those prioritizing low fees, fast market creation, and blockchain transparency. Meanwhile, Kalshi offers a more traditional approach, with regulatory protection, straightforward fiat onboarding, and interest-earning accounts for added value. Your choice will depend on which features align most with your trading goals.

Conclusion

When deciding between Polymarket and Kalshi, the best platform for you depends on your trading goals and priorities. Both platforms have distinct strengths, catering to different types of traders.

Polymarket offers deep liquidity, lower fees in many categories, and rapid market creation, making it a fit for high-frequency traders comfortable understanding the cryptocurrency space. Its on-chain transparency also allows for advanced strategies like tracking large market participants. However, its reliance on crypto and the need for self-managed tax reporting might pose challenges for those used to more traditional setups.

On the other hand, Kalshi offers a more conventional, regulated trading environment. With full CFTC oversight, FDIC-insured USD accounts, and automatic 1099 tax forms, it provides a streamlined experience for traders prioritizing regulatory compliance. The platform also offers tax benefits under Section 1256 for certain gains, potentially reducing tax rates for top earners. Additionally, balances of $250 or more earn a variable 3.50% APY. However, Kalshi’s higher fees in many categories, slower market creation due to regulatory reviews, and lower liquidity in niche markets might be drawbacks for some traders.

"Polymarket is the better trading venue for those who can access it - deeper markets, more choice, lower effective fees at scale, and full on-chain transparency. Kalshi is the right answer for U.S. residents and anyone who values regulatory certainty above all else".

Ultimately, the choice comes down to your trading style and risk tolerance. If you favor fast, cost-effective trading with a wide variety of markets, Polymarket is a great fit. For those who value regulatory certainty, fiat convenience, and tax efficiency, Kalshi is the better option. Maintaining accounts on both platforms could be a strategic move, allowing you to take advantage of their respective strengths, arbitrage opportunities across crypto and prediction markets, and optimal liquidity and fee structures for specific events.

Neither platform is inherently "better." Instead, they cater to different needs within the trading ecosystem. The right choice depends on your preferences, comfort with regulations, and technical expertise.

FAQs

Which platform is safer for U.S. traders?

Kalshi offers a safer environment for U.S. traders because it's a CFTC-regulated Designated Contract Market (DCM). This means it adheres to U.S. laws and provides legal protections that enhance user confidence. On the other hand, Polymarket's international platform, despite its broader market options and crypto-native approach, operates offshore and has faced regulatory challenges. Polymarket US is also a CFTC-regulated exchange, open to U.S. users after identity verification. For traders who value security and clear legal standing, Kalshi is the more reliable choice.

How do I minimize slippage and spreads on each platform?

To minimize slippage and spreads on Polymarket and Kalshi, focus on trading in markets with high liquidity and tight spreads. High liquidity ensures smoother trade execution and less price fluctuation.

Whenever possible, use limit orders instead of market orders. Limit orders let you set a specific price, helping you avoid unfavorable price movements that can occur with market orders.

Keep an eye on liquidity levels and adjust the size of your trades accordingly. Larger trades in low-liquidity markets can lead to significant slippage, so scaling down your trade size in such situations can help.

Lastly, stick to strict risk management practices. For example, limit your exposure to around 2–3% of your capital per trade. This approach helps reduce the financial impact of slippage and spreads while protecting your overall portfolio.

What do I need to do for taxes when trading Polymarket vs Kalshi?

Tax responsibilities for Polymarket and Kalshi vary based on their operations and regulatory classifications. Any profits earned are subject to taxation and might fall under categories like ordinary income, capital gains, or even gambling winnings, depending on the circumstances.

Kalshi issues 1099 forms, such as 1099-INT for interest, 1099-MISC for rewards and 1099-B for proceeds, when you meet IRS reporting thresholds (checked on 10 Oct 2026). On Polymarket, keep your own detailed record of every trade, and on either platform make sure you report all gains accurately. To stay compliant with IRS rules, it's a good idea to consult a tax professional who has experience with prediction markets.