For the week ending April 26, trading volume on Kalshi reached $3.4 billion according to Artemis. This is a new all-time high for the prediction market platform. But the main point is not the total volume, but its structure. Sports events accounted for about $3 billion, or 88% of Kalshi’s weekly turnover. This category alone processed about $1 billion more than the entire weekly volume of Polymarket.
To understand the scale of growth, just compare the numbers to last year. Back then, Kalshi’s weekly volume was about $80.5 million. Now, this figure has increased 42 times.
Sports Remain the Main Driver for Kalshi, and the Gap Only Grows
Looking at the breakdown by category, it becomes clear what the platform relies on. Of the $3.4 billion in total volume, about $3 billion came from sports markets, which is also a new all-time high. The crypto section lags far behind with $334.1 million, and politics brings in only $16.8 million, less than 0.5% of total turnover. The main contribution now comes from the NBA playoffs, which account for most of the activity.
Kalshi volume by category. Source: Artemis
And this is no accident. Kalshi originally built its growth around sports contracts. The platform offers lines on individual matches, spreads, and long-term bets on major leagues, in a format that attracts both experienced players and regular users. The numbers confirm this. Sports events account for more than 85% of Kalshi’s weekly turnover. Over the past year, the gap between sports and other categories has only widened, especially compared to political and financial markets.
Where Polymarket Still Holds Its Ground
Although for the week ending April 26, trading volume on Polymarket was about $1.4 billion less than on Kalshi, the distribution structure is completely different. The sports category saw $959.1 million, but politics showed $507.3 million, and crypto about $416 million. This is significantly higher than Kalshi in these segments. In total, Polymarket distributes volume across nine categories, making it appear more diversified.
Polymarket volume by category. Source: Artemis
The difference in politics is especially noticeable. Last week, Polymarket recorded $507.3 million in volume in this category, while Kalshi had only $16.8 million. The difference is about 30 to 1 in the segment where the prediction market industry as a whole began. A global audience and an established community of traders interested in politics give Polymarket a strong advantage that Kalshi with its focus on sports has not yet been able to offset. Markets related to the 2028 elections, geopolitics, and international events are still mainly traded through Polymarket.
Two Platforms, Two Different Models
These numbers show that Kalshi and Polymarket are no longer really competing for the same user. Kalshi is actively entering the regulated sports betting market and is essentially playing on the field of DraftKings and FanDuel, only in the prediction market format.
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Polymarket remains a platform for those who want to trade on election outcomes, macroeconomic events, and the crypto market, with global liquidity and participants from all over the world.
