Kalshi and Polymarket open interest drops 20%, World Cup buzz cools off

PANews July 21—According to The Block, ahead of the FIFA World Cup final, the combined open interest of Kalshi and Polymarket fell by 20% from the approximate $2 billion peak in early July, dropping from about $1.8 billion to around $1.5 billion. Kalshi’s sports event trading volume hit a peak of about $9 billion in the week of July 5, then fell to about $4 billion, while Polymarket dropped from about $2.3 billion to $740 million. During the World Cup, sports events accounted for roughly 80% of the total trading volume across the two major platforms. On Sunday, Spain beat Argentina 1-0 to win their second World Cup title in history.

Polymarket profit and loss data compiled by DeFiOasis shows that 194k addresses traded Polymarket’s World Cup champion market, with about two-thirds losing. Most gains and losses were under $100, while 54 addresses earned more than $100k each; five of them exceeded $1 million, and 43 addresses each lost more than $100k. With the World Cup over, prediction market activity may remain subdued until the U.S. midterm election cycle brings the next major catalyst.