The Vig Arrives: Polymarket Fees and the Sportsbook-ification of Prediction Markets

The free ride is officially over. On March 30, 2026, Polymarket flips the switch on taker fees across nearly every market category on its platform — completing a three-month transition from the zero-fee growth experiment that fueled its meteoric rise into a revenue-generating exchange projecting north of $200 million annually. For a platform that built its $20 billion valuation on frictionless trading, the introduction of a vig marks the most consequential structural change in its history.

What’s Changing on March 30

Polymarket’s fee rollout has been deliberate and phased. In January 2026, the platform introduced its first-ever trading fees on 15-minute, 5-minute, and hourly crypto prediction markets — the high-frequency arenas dominated by bot traders. In February, sports markets followed. Now, on March 30, the remaining eight categories go live: Finance, Politics, Economics, Culture, Weather, Tech, Mentions, and Other/General.

One category gets a permanent exemption: geopolitics and world events markets will remain fee-free. Polymarket hasn’t elaborated on why, but the category’s sensitivity — and its history of insider trading scrutiny — likely makes it a poor candidate for adding friction.

The announcement itself was notably quiet. Rather than a blog post or press release, Polymarket updated its documentation pages. Many traders may not realize fees are coming until they see the deduction on their first post-March 30 trade.

How the Fee Formula Works

Polymarket didn’t opt for the simple flat-rate approach. Instead, the platform uses a dynamic, probability-based formula that adjusts fees based on how close an event is to a coin flip:

fee = C × p × feeRate × (p × (1 – p))^exponent

Where C is the number of shares traded, p is the share price (representing probability), feeRate is a category-specific parameter, and the exponent shapes the curve. The result is a symmetrical bell curve that peaks at exactly 50% probability and drops toward zero as outcomes approach certainty.

The rationale is intuitive: it’s far riskier to provide liquidity when an event is a genuine toss-up than when it’s nearly certain. A market trading at $0.50 (50/50 odds) generates the maximum fee. A market at $0.95 or $0.05 generates almost nothing. This means traders buying long shots or near-certainties are barely affected — the fee disproportionately hits positions on competitive, high-uncertainty events.

Category-by-Category Fee Breakdown

Each market category on Polymarket has its own fee parameters, creating a tiered structure where some categories cost significantly more to trade than others. The peak effective rate is what a taker pays at 50% probability — the worst-case scenario. At more extreme prices, fees shrink dramatically.

Important caveat: fees only apply to new markets deployed on or after each category's activation date. Existing legacy markets within a category may remain fee-free until they resolve. Also worth noting — winning shares always redeem at exactly $1.00 USDC with zero deduction. The vig is on the trade, not the payout.

The Sportsbook Comparison — Still the Cheapest Game in Town

Here's where the "sportsbook-ification" narrative gets interesting: even with the vig, Polymarket remains dramatically cheaper than every traditional alternative. The standard sportsbook charges roughly 4.5-5% through the familiar -110 juice on both sides of a bet. FanDuel Predicts and DraftKings Predictions — the sportsbook industry's answer to prediction markets — maintain an identical 5.0% house take.

On a $1,000 position at even odds, the math tells the story: a Polymarket sports taker pays roughly $7.50. A Kalshi trader pays $12. A FanDuel Predicts user pays $50. That's a nearly 7x cost advantage — the kind of structural edge that makes migration from traditional platforms almost irrational not to consider (see our house edge guide for how these percentages compound over time).

The Polymarket US platform (the regulated DCM exchange) is even cheaper at a flat 0.30% taker fee — though it has a narrower market selection and requires KYC verification for U.S. residents.

Where the Money Goes — Maker Rebates

Polymarket isn't pocketing the fees — at least not directly. One hundred percent of collected taker fees are redistributed to market makers through the Maker Rebates Program. Liquidity providers who place limit orders (makers) pay zero fees and receive daily USDC payments proportional to their contribution to market depth.

The rebate rates vary by category. Finance markets offer the most generous 50% rebate, incentivizing deep liquidity in what Polymarket apparently views as a key growth area. Most other categories offer 25%, while crypto gets 20%. The goal is a virtuous cycle: taker fees fund maker rebates, which attract more liquidity providers, which tighten spreads, which attract more takers — even if those takers are now paying a small toll.

Winners and Losers

Polymarket US vs. International

The fee structures diverge significantly between Polymarket's two platforms. The international platform (the original crypto-based exchange) uses the dynamic probability-based formula described above, with category-specific parameters. The U.S. platform — a CFTC-regulated Designated Contract Market (DCM) — uses a simpler structure: a flat 0.30% taker fee and a 0.20% maker rebate on total contract premium.

For U.S. traders with access to both, the regulated DCM is significantly cheaper in almost every scenario. The tradeoff is a smaller market selection and the requirement to complete identity verification.

The Regulatory Shadow

The fee rollout doesn't exist in a vacuum. Polymarket is simultaneously navigating an increasingly complex regulatory landscape. A bipartisan Senate bill — the "Prediction Markets Are Gambling Act" introduced by Senators Adam Schiff and John Curtis — seeks to prohibit CFTC-registered entities from listing sports or casino-style prediction contracts. If passed, it would strike directly at Polymarket's sports vertical, which is backed by a reported multi-year deal with Major League Baseball worth up to $300 million.

Alongside the fee expansion, Polymarket also introduced new market integrity rules prohibiting trading on misappropriated confidential data, unlawfully obtained information, or by parties capable of influencing event outcomes. These rules — clearly a response to repeated questions about prediction market integrity — signal that Polymarket is trying to mature its governance framework in step with its monetization.

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Sources

• Trading Fees Documentation — Polymarket Official Docs
• Maker Rebates Program — Polymarket Official Docs
• Polymarket US DCM Fee Schedule — Polymarket Exchange
• Polymarket Is Done Being Free — Benzinga
• Polymarket Set to Earn Around $1 Million a Day — Finbold
• Prediction Market Fees Compared — DeFi Rate