Weekly spot volumes across prediction market platforms reached its highest level this past week as the FIFA World Cup got underway. Weekly volumes crossed the $8 billion mark, hitting $8.7 billion last week, crossing the previous high of $7.4 billion set in early February this year. No election cycle or crypto blowup had managed to drag the category past that line before. A month-long tournament did it in the opening seven days.
Source: Artemis

When looking at the market share split, Kalshi continues to take the bulk of it. Its weekly spot volume hit $5.1 billion, a platform high and the only individual record set during the week. Polymarket came in second at $3 billion. Kalshi went into the tournament already ahead and the World Cup was shaping up as Polymarket’s chance to fight back. Instead Kalshi stretched its lead.
Sports contracts have been the main driver for Kalshi’s volumes for months. The expanded 48-team World Cup has effectively turbo charged this driver. Dozens of matches across a multi-week schedule mean a constant supply of fresh markets. The $5.1 billion weekly spot volume isn’t just a number that looks good against Polymarket since it’s the highest figure ever recorded by any platform within this sector.
Polymarket’s $3.0 billion would have been a standout in almost any other week. In fact, the $3 billion mark equals its record posted in the week ending April 12. That said, the gap that existed between the two largest prediction market platforms before the World Cup began continues to hold.
Polymarket isn’t standing still. A beta version of combos on Polymarket for World Cup matches was launched two days ago. This is basically parlay-style bundles that allows users to stack several World Cup outcomes into one position, mirroring the multi-leg bets traditional sportsbooks use, a response to capture some of the sports category volume dominated by Kalshi.
VP of engineering Josh Stevens said more is coming over the next few weeks, pointing to additional market types, more sports categories, and continued work on the UI and UX. The takeaway is that combos are a starting point rather than the full pitch. Polymarket is trying to out-build its way back into the race instead of out-spending it.
The more interesting move is happening beneath the big two. Robinhood began routing some of its World Cup contracts through Rothera, the CFTC-regulated exchange it co-owns with Susquehanna, rather than sending all of it to Kalshi. Rothera posted $170.3 million for the week.
That number is tiny. Set against Kalshi’s $5.1 billion it barely registers. But Rothera only began trading on June 1, 2026, and cleared about $2 million in its first week. The jump to $170.3 million as the tournament got underway shows how fast Robinhood can move volume once it decides to keep flow in-house. In fact, just yesterday, data from Dune Analytics shows that Rothera posted $109.2 million in a single day.
Source: Dune
The direction is what counts. Robinhood users have made up close to a quarter of Kalshi’s trading volume, and every contract rerouted to Rothera is volume Kalshi no longer books. A platform that owns its own distribution and decides to keep more of it in-house is a different kind of competitor than another standalone exchange trying to win traders one at a time.
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