Sports contract costs favor Polymarket US in weekly venue comparison
Tater Research measured the two-sided cost, fees included, across 170 games in the week ending November 2 at 3.90 cents per dollar of payout on Kalshi and 3.57 cents on Polymarket US, against 4.42 cents at a typical sportsbook. On settled games Polymarket US posted a Brier score of 0.375 and Kalshi 0.380, against 0.382 for sportsbooks on the same games.
Tater Research measured the fee-inclusive cost of holding both sides of a sports game across 170 games in the week ending November 2. The cost per dollar of payout was 3.90 cents on Kalshi and 3.57 cents on Polymarket US, compared with 4.42 cents at a typical sportsbook.
Costs and forecast accuracy
According to Tater Research, both prediction-market venues had lower two-sided costs than the typical sportsbook benchmark in that weekly sample. Polymarket US recorded the lowest cost of the three.
The research also assessed forecast accuracy for settled games using Brier scores. Polymarket US scored 0.375, Kalshi scored 0.380, and sportsbooks scored 0.382 on the same games.
Polymarket US therefore recorded both the lowest measured transaction cost and the lowest Brier score in the comparison. The findings cover the specified weekly sample, rather than establishing how the venues compare over longer periods.
What it means for prediction markets
- Fee-inclusive comparisons matter: The two-sided cost measure incorporates fees, providing a comparison beyond displayed contract prices.
- The cost benchmark favored prediction markets: Kalshi and Polymarket US both came below the typical sportsbook’s 4.42 cents per dollar of payout.
- Accuracy was measured separately: The settled-game Brier scores provide another comparison alongside costs, with results limited to the games assessed.
Sources & attribution
- Published
- Source
- Tater Research
- Publisher
- The publisher did not list a web address.
- Source URL
- The feed did not publish this story's article address.
Full attribution under the Digital Millennium Copyright Act (DMCA), 17 U.S.C. § 512: this article is an original report by Infiniti Intelligence that summarizes the reporting of the publishers named above, links to their original work, and reproduces no protected expression beyond brief factual reference and in-line attribution (“according to Tater Research”). All rights in the underlying reporting remain with the publishers listed; nothing here implies endorsement by or affiliation with them. Rights holders may request correction, update or removal through the contact address published at infiniti.w3ai.io.
Related
- Second Circuit denies Kalshi and Coinbase injunctions pending appeal in New York and Connecticut cases, iGaming Times reports
- Kalshi projects Jon Ossoff as the winner of the Georgia Senate race at 99 percent, Kalshi News reports
- Democrats holding above 249 House seats priced at 96.8 cents on Kalshi on 914,000 dollars traded in 24 hours, DeFi Rate reports
- Coatue, Balyasny and Millennium back Kalshi in its 1 billion dollar funding round at a 40 billion dollar valuation, AlphaMaven reports
- Georgia Bulldogs lead the college football championship market at 22 percent on Kalshi and Polymarket, up 2 points, Rivo reports
- The First Circuit hears oral argument this morning in Robinhood's Massachusetts prediction-market case, the next appellate test of state power over event contracts