Polymarket Vs Kalshi: Where Are Fans Placing Their Fifa World Cup Predictions?

What Happened

Elections, the category that made Kalshi famous, managed just $173.66 million that month, roughly 60 times less.

Note: All weekly data points have been condensed into monthly data points.

The peak came in March, when sports did $8.77 billion of a record $19.58 billion in a month. By June this time, the total had cooled about 70% to $5.91 billion, yet the sports share climbed to 56.5%. Crypto held $1.73 billion and politics shrank to $831.25 million.

Market Context

FIFA World Cup predictions have become the biggest business in prediction markets. Polymarket’s tournament winner market alone holds $2 billion in bets, while Kalshi runs 48 markets on the same question and banks the industry’s largest fees.

The two platforms agree on the football yet split the money in very different ways. BeInCrypto’s Dune dashboards across three venues show where volume, fees, and leftover crypto bets sit.

Sports Built a Record May for Prediction Markets

By Binance Research’s accounting, prediction markets turned over a record $31.2 billion in May, up roughly 15% from January. The same report puts Kalshi at 58% of that flow and Polymarket at 28%, with industry open interest reaching $1.3 billion.

BeInCrypto’s own data shows what filled Kalshi’s share. In the platform’s biggest month of 2026, that is May, sports trading volume reached $10.44 billion.

Crypto markets did $2.02 billion on Kalshi in the same period, while a sports-adjacent exotics bucket added $4.88 billion more. The pattern suggests the 2026 World Cup calendar, not politics or coin prices, now powers the platform’s growth.

The single biggest football market shows how concentrated that engine is.

One $2 Billion Market Against 48 Smaller Ones

Polymarket’s World Cup Winner market holds $2 billion in lifetime volume, $436 million in liquidity, and traded $137 million on Thursday alone. The platform’s FIFA World Cup section spans more than 330 active markets.

Kalshi’s equivalent event has built $182.3 million across 48 markets. On the largest listed events, the gap runs roughly 11 to 1 in Polymarket’s favor, and Thursday’s flow on Polymarket alone approached the lifetime volume of Kalshi’s biggest listed World Cup event.

The venues disagree on structure, not on football. Both books price the World Cup odds identically, with Spain favorite at exactly 17% and Kalshi paying 5.56x on Spain and France alike.

Kalshi spreads flow across dozens of match-level books while Polymarket pools it in one tournament-scale market. Kalshi still clears more total volume platform-wide, per Binance Research’s 58% share, so the contest is breadth against depth rather than big against small.

That concentration shows up across Polymarket’s entire year.

Sports have Led Polymarket All Year, and It’s Cooling

Sports topped every weekly category split on Polymarket in 2026. January saw sports at $6.20 billion, or 43% of the $14.34 billion total, ahead of politics at $4.49 billion and crypto at $3.65 billion.

In other words, football dominance is not a tournament artifact. It predates the World Cup hype, and it deepens even as overall activity cools into the group stage.

Volume tells half the story. The fees tell the rest.

In May, Kalshi collected $137.86 million in trading fees, compared with Polymarket’s $28.07 million and Opinion’s $159,330. That is nearly a five-to-one revenue gap, consistent with Binance Research’s finding that Kalshi clears the most volume.

The dashboard tracks Kalshi fees from April onward, and both tracked months sit far above anything Polymarket has earned. So the betting money splits two ways, but the fee money flows overwhelmingly to Kalshi.

Why It Matters

June is already seeing Sports lead the way. And with almost the entire World Cup fixture to go, this figure might surge. It is worth mentioning that the Elections category on Kalshi is already nearing its May levels. This category might therefore steal some of Sports’ thunder.

Details

Kalshi Takes the Fees, Opinion Shows the Endgame