Prediction market platform Kalshi processed a record $3.4 billion in trading volume during the week ending April 26, according to data from Artemis. This new all-time high represents a staggering 42x increase from the $80.5 million weekly volume recorded just one year ago.
The standout figure, however, is not the total volume but its composition. Sports markets alone accounted for $3 billion—88% of Kalshi's weekly trading. This single category exceeded the entire weekly volume of rival platform Polymarket by roughly $1 billion. The NBA playoffs were identified as the main driver behind the surging sports volume.
Kalshi's growth strategy has focused heavily on sports contracts, offering per-game moneylines, spreads, and futures across major leagues. This approach has attracted both sharp bettors and casual traders, making sports event contracts account for over 85% of weekly turnover. Meanwhile, Kalshi's crypto markets ranked a distant second at $334.1 million, while politics generated just $16.8 million—barely half a percent of total volume.
Polymarket, while posting roughly $1.4 billion less in weekly volume, maintains a fundamentally different structure. Its sports category totaled $959.1 million, but political markets generated $507.3 million and crypto saw around $416 million. Spread across nine categories, Polymarket's volume is significantly more diversified. The gap in political markets is especially stark: Polymarket logged $507.3 million versus Kalshi's $16.8 million—a roughly 30-to-1 disparity.
The data suggests that Kalshi and Polymarket are no longer competing for the same users. Kalshi is pursuing the regulated sports betting market, challenging DraftKings and FanDuel with a prediction market wrapper. Polymarket serves as the venue for trading on elections, macro events, and crypto outcomes with a global counterparty pool.
