Kalshi accounts for 88% of prediction market debit transactions year to date
Kalshi accounted for 88% of all prediction market debit transactions year to date through August, according to card spending data. The platform also recorded the lowest average purchase amount among prediction market operators. The data comes from a broader report on debit card spending trends. No specific contract types or dollar volumes were disclosed alongside the transaction share figure. The figure was cited in reports by Credit Union Times and other outlets covering online gambling patterns among members.
The 88% debit share shows Kalshi has built a retail deposit base that dwarfs every competitor in frequency of use. That matters because debit purchases typically reflect smaller, recurring trader commitment — the kind of habitual engagement platforms convert to higher-margin products. Kalshi's lowest average ticket size among operators reinforces this: it is winning on volume of users, not size of whales.
For Polymarket and Novig, the data signals a retail gap to close before the midterms. The catch is durability. Debit dominance in August does not guarantee stickiness into political season. Platforms that cannot match Kalshi's onboarding friction and payment integration will watch that retail base harden into a moat.