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Polymarket’s single World Cup winner market crossed $2 billion in total bets. Kalshi, meanwhile, spread its football action across 48 separate match-level books — and pulled in $137.86 million in trading fees just in May. Two very different playbooks. One very loud tournament.
The gap between those two numbers tells you pretty much everything about how these platforms are built. Polymarket concentrates liquidity into one massive pool. Kalshi fragments it across dozens of smaller markets. Neither approach is obviously wrong, but the fee numbers don’t lie — Kalshi’s $137.86 million dwarfs Polymarket’s $28.07 million in May revenue, even though Polymarket’s single World Cup market is bigger in raw volume than anything Kalshi has touched on the tournament. It’s basically a case of depth versus breadth, and right now breadth is winning on the income statement.
May Numbers Were Staggering Across the Board
May was a record month. Prediction markets collectively turned over $31.2 billion — a figure that would have seemed absurd even two years ago. Kalshi took 58% of that flow. Polymarket took 28%. The rest went elsewhere. Sports drove most of it. Kalshi’s sports trading volume alone hit $10.44 billion in May, which isn’t just big relative to prediction markets — it’s big, full stop. Compare that to Kalshi’s elections category, which managed $173.66 million in the same month. Politics used to be the whole point of these platforms. Now it’s a rounding error next to football.
That’s a real shift. Not a blip.
Sports predictions have basically eaten the rest of the prediction market menu. Crypto markets, political betting, economic forecasts — all of it is getting overshadowed by match-level football books and tournament winner pools. It’s unclear whether this is a permanent structural change or just World Cup noise, but the scale of May’s numbers makes it hard to dismiss as a seasonal spike. Kalshi’s sports volume being nearly 60 times larger than its elections volume in the same month is a pretty stark data point.
Polymarket’s $2 Billion Pool vs. Kalshi’s 48 Markets
Polymarket’s World Cup winner market sits at $2 billion in lifetime bets. Kalshi’s 48 World Cup markets combined reached $182.3 million. So Polymarket’s single market is roughly eleven times larger than everything Kalshi has built around the tournament. That’s concentration working exactly as designed — traders who want to bet on who lifts the trophy go to Polymarket, full stop, because that’s where the liquidity is.
But Kalshi isn’t really competing for that same bettor.
Kalshi’s match-level books target people who want to bet on Tuesday’s specific game, not the tournament winner six weeks from now. Those bettors are different. They’re probably more active, probably making more frequent smaller bets, and they generate transaction volume that compounds fast across 48 markets. That’s probably why Kalshi’s fee revenue is nearly five times Polymarket’s despite Polymarket owning the headline number.
And the group stage helps Kalshi’s model specifically. Daily games mean daily markets, daily volume, daily fees. Polymarket’s tournament winner pool doesn’t benefit from that same cadence — it just sits there accumulating until someone lifts a trophy. In the knockout rounds, when daily games thin out and the stakes per match rise, Polymarket’s deep pool might start pulling more attention. That’s the theory, anyway. Unclear how it actually plays out.
What the Fee Gap Actually Means
$137.86 million versus $28.07 million. In one month. That’s the fee gap between Kalshi and Polymarket in May, and it’s worth sitting with for a second.
Fee revenue is how you run a business. Volume is how you attract press. Polymarket gets the headlines because $2 billion in a single market is a genuinely wild number and easy to write about. Kalshi gets the revenue because it’s running what amounts to a high-frequency sports book distributed across dozens of markets simultaneously. Both platforms are growing. But if you’re thinking about which model scales better as a business, the fee numbers probably matter more than the headline volume figures.
Sports categories have now overtaken crypto and politics on every major prediction platform. That’s not just a Kalshi or Polymarket story — it’s an industry-wide reorientation. Platforms that built their identities around election markets are now rushing to build out sports infrastructure. The World Cup accelerated something that was already happening.
Kalshi’s elections category at $173.66 million in May used to represent the core product. Now it looks like a side offering. Sports is the core. Football is the engine. And the 2026 World Cup is probably the single biggest catalyst these platforms have ever had.
Polymarket’s $2 billion pool still leads the tournament winner category by a distance nobody is catching in the remaining weeks of play.
Frequently Asked Questions
How much has Polymarket’s World Cup winner market accumulated in total bets?
Polymarket’s World Cup winner market reached $2 billion in lifetime bets, compared to $182.3 million spread across Kalshi’s 48 World Cup markets combined.
How did Kalshi and Polymarket split prediction market volume in May?
In May, prediction markets turned over $31.2 billion in total. Kalshi accounted for 58% of that flow, while Polymarket captured 28%.
Why did Kalshi earn more in trading fees than Polymarket despite lower World Cup volume?
Kalshi earned $137.86 million in trading fees in May versus Polymarket’s $28.07 million, largely because Kalshi spreads activity across dozens of match-level markets rather than concentrating bets in a single pool.
