Prediction Markets Post $50.6B July Record as Supreme Court Countdown Begins

Prediction markets notched a record in July, but trading activity also showed a sharp “cliff” after the World Cup ended. Kalshi, Polymarket and Polymarket US combined for $50.59 billion in volume, up 7.8% from June’s $46.95 billion, according to The Block. The surge was driven largely by the 2026 FIFA World Cup, which also coincided with legal pressure: New York’s attorney general filed a $36 billion civil enforcement suit against Kalshi, and New Jersey faces an August 4 deadline to petition the U.S. Supreme Court. Despite the headline volume, open interest fell about 40% from roughly $2 billion to ~$1.2 billion, as positions resolved and traders left.