Kalshi Weekly Volume Hits $3.4B on NBA Playoffs

Kalshi processed $3.4 billion in trading in the week ending April 26, with $3 billion of that tied to sports markets led by the NBA playoffs, according to Artemis data. The total is a new all-time high for the regulated prediction market operator and exceeds Polymarket’s reported weekly volume by roughly $1 billion.

Kalshi’s week marked a sharp rise from its average weekly volume a year earlier, which was about $80.5 million. Sports markets made up roughly 88% of last week’s activity. Crypto markets recorded $334.1 million, and the politics category generated $16.8 million, about 0.5% of the week’s volume.

Kalshi offers per-game moneylines, spreads and futures across major sports leagues. The NBA playoff schedule produced a concentrated stream of per-game markets that corresponded with the surge in activity.

Polymarket reported lower total volume for the same week, with its distribution spread across nine categories. Polymarket recorded about $959.1 million in sports volume, $507.3 million in political markets and roughly $416 million in crypto-related trading.

Political volume differed sharply between the two platforms: Polymarket’s political markets totaled $507.3 million versus Kalshi’s $16.8 million, a roughly 30-to-1 gap. Polymarket lists markets covering the 2028 U.S. presidential race, geopolitical events and international elections.

The two platforms showed distinct product mixes. Kalshi’s activity was concentrated in high-frequency sports event contracts within a regulated framework. Polymarket’s activity was distributed across political, crypto and macro markets with broader category coverage.

Sports event contracts accounted for more than 85% of Kalshi’s weekly turnover. The data highlights the differences in how the two operators attract trading volume and the categories that led activity in the week ending April 26.