DeFi Rate price comparison shows Kalshi and Polymarket diverge on NFL Week 8 lines
DeFi Rate published a price comparison for NFL Week 8 event contracts across Kalshi and Polymarket on Monday. The Detroit Lions are favored over the Minnesota Vikings, while the Kansas City Chiefs–Denver Broncos market is priced much tighter between the two venues. The comparison covers all 14 games on the Week 8 slate. Kalshi separately posted Panthers at 36% and Packers at 65% for the October 29 Thursday Night Football matchup.
Price divergences between CFTC-regulated venues are rare enough that traders notice them. Kalshi and Polymarket post different lines on the same Chiefs-Broncos outcome, the gap is an arbitrage signal for sophisticated users and a quality-control alarm for everyone else. The tighter the market, the more sensitive traders are to which venue offers the better number.
Kalshi still depends on FanDuel's market-making partnership for the liquidity behind its prices. Polymarket's international user base and different fee structure may explain some of the variance. Sustained divergences would push volume toward whichever venue posts the sharper line, eroding the 76% share Kalshi holds per Needham data.
Joins a string of recent Kalshi sports pricing stories that now includes NFL Week 7 moneylines, point spreads, totals, and division futures alongside Kalshi's retaken pricing edge from FanDuel and DraftKings in Week 4.