Polymarket Undercuts Kalshi on Fees

The fee gap matters because prediction markets are becoming a commodity exchange business where the cheapest venue with the deepest book tends to pull in both bettors and market makers. Polymarket can charge less because trades settle on Polygon with user supplied liquidity, zero maker fees, and rebate funded incentives, while Kalshi runs a regulated U.S. exchange with a clearing stack that carries more overhead. At 50 cents, Polymarket U.S. charges $1.25 per 100 contracts before rebate caps, versus Kalshi at about $1.75 per 100 contracts, which is why a roughly 1% Kalshi take rate stands out.1 2 3 4 5

• Polymarket does not make a spread as principal. It matches one user against another, charges only takers, and uses those fees to pay maker rebates. That lets it keep the visible cost on the aggressive side of the trade low while still paying people to post resting orders.1 3
• Kalshi is not just pricier by policy, it is pricier by structure. Its official fee table reaches $1.75 per 100 contracts at 50 cents, and the company has described prediction markets as running at a blended fee of roughly 1.0%, reflecting a fiat, CFTC regulated exchange and clearing model rather than crypto rails.4 5
• The practical user impact shows up most in high frequency categories like sports. If traders are entering and exiting around live news, line movement, or arbitrage across venues, paying 30% less to 50% less per round trip compounds quickly and makes it easier for Polymarket to tighten spreads and recycle liquidity.1 2 4

This pushes the category toward a two track market. Kalshi is likely to keep winning where U.S. regulatory certainty and brokerage distribution matter most, while Polymarket keeps pressing on price and speed. If both continue scaling, fees should keep compressing and the real differentiators will shift to liquidity density, market breadth, and distribution.2 3 4 5