Kalshi recorded $37.17 billion in trading volume in August, down 7.3% from July’s $40.1 billion. Polymarket, together with the U.S. platform, accounted for an additional $8.16 billion, compared to $12.89 billion the previous month—a 36.7% decline, according to the Fixygen portal.
At the same time, after record activity in the summer, trading volume fell by 14.5% compared with July. This was the first monthly decline in approximately a year, according to data from The Block.
Kalshi accounted for $37.17 billion in turnover in August, which was 7.3% less than July’s $40.1 billion. Polymarket together with the U.S. platform generated another $8.16 billion compared with $12.89 billion a month earlier, meaning volume declined by 36.7%.
However, even after the decline, the August market remained significantly larger than in May, when combined turnover amounted to around $25.66 billion.
This segment is developing especially rapidly within traditional brokerage platforms.
Robinhood reported on September 8 that in the second quarter alone, 13.6 billion event contracts were traded through its service, while in the first eight months of 2026 more than 30 billion contracts were traded. Since the launch of the business about two years ago, Robinhood clients have entered into more than 45 billion such contracts.
The company is expanding the number of venues through which trades are executed. In addition to Kalshi and ForecastEx, Robinhood uses Rothera, and from September 8 began routing some contracts to the Crypto.com platform through CFTC-regulated infrastructure.
The company is also launching a separate prediction markets section for the U.S. midterm elections and expanding its offering of contracts on American football.
Prediction markets allow participants to buy and sell contracts whose payouts depend on the occurrence of a specific event — the result of a sports match, an election, an economic indicator or another measurable event.
In terms of their economic structure, such instruments lie between financial derivatives and traditional betting, which simultaneously ensures their rapid growth and creates regulatory disputes.
In the United States, more than ten states have already taken legal or administrative action against Kalshi or Polymarket, primarily over sports contracts.
CRYPTOCURRENCY, KALSHI, Polymarket, PREDICTION MARKETS, ROBINHOOD
