The combined open interest on leading prediction platforms Kalshi and Polymarket fell nearly 20% from its early July peak of approximately $2 billion following Spain's 1-0 victory over Argentina in the World Cup final. This decline signals a sharp reduction in speculative activity linked to the tournament.
Decline in Transaction Volumes After World Cup
Sports betting made up about 80% of total volumes during the World Cup on both Kalshi and Polymarket. Weekly volumes on Kalshi decreased by nearly 55%, falling from around $9 billion during the week of July 5 to about $4 billion by July 19. Polymarket saw an even steeper drop of nearly 70%, with volumes decreasing from approximately $2.3 billion to $740 million over the same period. The reduction in volumes is tied to the tournament's progression, where the high frequency of daily matches during the group stage supported continuous capital rotation. As the event moved into knockout rounds, fewer matches were available daily, reducing market offerings for bettors.
User Profitability and Market Dynamics
Analysis of World Cup-related betting portfolios on these decentralized prediction markets revealed that two-thirds of the 194,000 unique addresses active on Polymarket incurred losses. Most balance changes were under $100, although a small number of 54 addresses generated profits exceeding $100,000 each. Despite a sharper fall in transactional volumes, open interest declined more gradually as capital remained locked until contracts were officially settled. This highlights the platforms' reliance on high-profile sporting events to sustain user engagement and trading activity.
