Kalshi Captures 87% of U.S. Prediction Market Volume Using Sports as Acquisition Funnel

Published by James Harris on July 7, 2026July 7, 2026

Prediction markets recorded their first-ever non-sports weekly volume above $4 billion last week, with the combined Kalshi and Polymarket figure landing at $4.4 billion according to Artemis data, even as the FIFA World Cup was simultaneously driving record sports volume on both platforms. Kalshi alone accounted for $3.8 billion of that non-sports total.

The more interesting story is not the number itself but what generated it. The World Cup appears to be functioning as an acquisition funnel: new users arrive for sports contracts, fund their accounts, and then migrate into politics, macro, and event markets without leaving. Kalshi’s non-sports spike tracks almost precisely to the tournament start date on June 11, and its American-skewing user base was already primed by a mobile product built to feel like a sportsbook, one with a regulated wrapper that gives retail traders a reason to stay. That regulatory positioning matters here. Polymarket’s 2022 CFTC settlement pushed it offshore, while Kalshi’s approach has run in the opposite direction, and that difference in legal standing is now showing up directly in which platform captures domestic non-sports volume. Polymarket drew $572.9 million in non-sports volume last week, less than a sixth of Kalshi’s figure.

The $4.4 billion headline is a ceiling to test, not a floor to build from.

Weekly combined volume across prediction markets hit $8.7 billion last week when sports is included, a category record, but that figure is almost entirely a function of a tournament that ends July 19. Polymarket’s sports side alone saw $2.51 billion, and its “tournament winner” market crossed $2.5 billion in isolation, meaning a single contract drove volume comparable to an entire platform’s weekly non-sports output. That concentration should temper how confidently anyone reads the current non-sports growth as structural rather than borrowed.

The real data arrives in August. If non-sports volume retreats toward the $1 to $2 billion weekly range that held through most of this year, the World Cup will have been a rental, not a conversion. If it holds anywhere near current levels, both platforms will have demonstrated something the prediction market sector has been trying to prove for years: that a sports audience can be cross-sold into a general-purpose trading behavior. The two platforms are structurally different enough that the outcome may diverge, with Kalshi’s regulated domestic base more likely to retain political and macro traders than Polymarket’s internationally dispersed crowd.