Prediction market open interest hit a record $1.48 billion in the week ending June 15, according to a16z crypto. That's a roughly sixfold increase over the past year. Weekly fees also peaked at $76.8 million, and active users hit an all-time high of 426,975.
World Cup fuels sports betting boom
Sports-related markets accounted for $5.8 billion of the total $12.2 billion in notional volume during the week. Nearly half the action came from sports. The 2026 FIFA World Cup is the main driver. Some users placed seven-figure wagers on individual matches. One trader reportedly generated $9.24 million in profits in a single day.
Platforms see record user activity
Most of the open interest sits on Kalshi and Polymarket. Smaller venues include Opinion, Limitless, and Myriad. The sustained climb shows traders holding longer-term positions across politics, economics, culture, and crypto. Open interest tracks capital participants keep deployed and at risk. It's different from trading volume, which measures turnover.
Beyond sports: a broader rally
Sports dominate, but the growth isn't limited to the World Cup. Categories like politics, economics, and culture also attracted capital. The second consecutive weekly peak, per a16z crypto, suggests a broader shift in how traders use prediction markets. Whether the trend holds after the tournament ends remains an open question.
