Polymarket US has introduced volume-based taker fees, making standard trades approximately 36% more expensive than on Kalshi for customers in its lowest-volume tier.
The news intensifies the debate over the cost of actively trading prediction markets.
Traders with less than $10,000 in qualifying 30-day taker volume face the highest rate, while those reaching $250,000 retain the previous standard coefficient.
New Fee Tiers Raise Costs for Smaller Traders
Polymarket US calculates standard taker fees using a coefficient multiplied by contract quantity, price and one minus the price.
Takers remove liquidity ,by executing against orders already available on the exchange.
For a purchase at 50 cents, the new tiers produce these costs before rounding and rebates:
| Trailing 30-day taker volume |
Fee as a percentage of purchase value |
| Below $10,000 |
4.75% |
| $10,000 to below $50,000 |
4.25% |
| $50,000 to below $250,000 |
3.75% |
| $250,000 or more |
3.475% |
New accounts receive the lowest coefficient for their first seven calendar days, regardless of volume.
November transition provisions can also give existing customers a more favorable tier.
Kalshi’s standard formula produces a $1.75 taker fee on 100 contracts bought at 50 cents, equivalent to 3.5% of the $50 purchase value.
Polymarket US’s lowest-volume coefficient yields an unrounded charge of $2.375, approximately 35.7% higher.
Repeated Trading Can Consume a Small Predictive Edge
The rollout drew criticism from traders who argued that repeated taker executions can overwhelm otherwise profitable strategies.
X account @Autonomous_Chad highlighted the gap with Kalshi, while @mahdiofalltime argued that frequent entries and exits impose substantial cumulative costs.
At Kalshi’s standard rate near 50 cents, six executions across three completed round trips cost approximately 10.5 cents per contract in fees.
Assuming an additional one-cent spread cost per round trip, total execution expenses reach approximately 13.5 cents, equaling 27% of an initial 50-cent position value
Under those assumptions, each round trip requires approximately 4.5 cents of favorable price movement merely to offset fees and spread costs.
Fee Comparisons Depend on Execution and Account Status
Posting resting orders can change the economics because maker and taker treatment differs.
However, a limit order that executes immediately against an existing quote still removes liquidity and attracts taker charges.
Polymarket US offers taker rebates beginning at $250,000 of qualifying volume, while maker rebates begin at substantially higher thresholds.
Its fee tiers now use a rolling window covering the preceding 30 completed Eastern Time calendar days.
Kalshi likewise lists exceptions in Eastern Time, meaning its standard formula does not describe every contract.
For traders, a platform with higher explicit fees could offer a better available price or deeper liquidity, while a cheaper venue could impose greater spread or slippage costs.
The new schedule makes account volume more consequential, particularly for smaller traders repeatedly executing near the midpoint of prediction-market prices.
