Prediction market platforms posted their strongest recorded week during April 6–11, with sports, politics and geopolitical trading pushing combined volume to new highs. Activity surged around the Masters Tournament, U.S. election-related markets and international events, led by Kalshi and Polymarket.

Tracked data showed Kalshi reached an all-time weekly best of $3.54 billion in notional volume, up 21.8% from the prior week. Polymarket followed with $2.48 billion, a 25.5% week-over-week increase. Together, the two platforms generated $6.02 billion for the week, edging past the previous combined high of $5.94 billion during the March 16 period when March Madness activity was at its peak.

Including other monitored platforms, total industry volume crossed $6.5 billion for the week.

Masters Becomes Kalshi’s Biggest Sports Event

The Masters delivered the main sports catalyst. According to DeFi Rate, Kalshi reported $545 million traded across tournament-related markets, making it the largest single sports event in the company’s history.

That figure included contracts on the outright champion, round leaders, scores on selected holes, head-to-head matchups and proposition markets. The main Masters winner market alone reached $460.3 million in notional volume, ranking second in Kalshi history behind only the 2024 presidential election winner market, which handled $535 million.

Rory McIlroy won the tournament after a volatile week at Augusta National. Reports said he held a six-shot lead after Friday, lost that advantage during Saturday’s round, then entered Sunday tied for first with Cameron Young before regaining the lead late and winning again. The result marked his second straight Masters title, making him the fourth golfer to win back-to-back at Augusta National according to the supplied reports.

Kalshi users could buy and sell contracts before market close, allowing live trading as leaderboard positions changed over the weekend.

Sports and exotics made up 85.8% of Kalshi’s weekly volume. Other sports products also contributed, including MLB, NBA, NHL and NCAA men’s basketball.

Polymarket Gains Through Politics and Macro Themes

While Kalshi’s week centered on sports, Polymarket’s biggest lift came from political and macro categories. The platform’s Trump-related markets rose 141% week over week to $488.3 million, while broader politics markets increased 58.7% in one cited dataset and $354.2 million in category volume.

Combined Trump and politics trading reached $842.5 million, or 34% of total Polymarket activity for the week.

Markets drawing attention included U.S.-Iran conflict contracts, 2028 U.S. presidential election positioning, April Federal Reserve rate decision markets, World Cup winner trading and Formula 1 championship markets.

Polymarket’s sports category also crossed $1.04 billion for the week, supported by more than $108 million across Masters-related markets. Crypto was the only major category to decline, slipping 5.9% to $474.6 million.

The platform generated $7.73 million in weekly fees and held 92.9% of all tracked on-chain prediction market fee revenue.

Trade Size Growth and Regulatory Questions

Transaction counts showed different user behavior across the two leaders. Kalshi processed 22.2 million transactions during the week, while Polymarket handled 22.3 million. Despite similar counts, Kalshi held more than a $1 billion volume lead, indicating larger average trade sizes.

Average trade size on Kalshi was about $159.70, compared with $110.77 on Polymarket. Supplied market analysis suggested Kalshi’s sports-heavy customer base tends to place larger individual wagers, while Polymarket users more often trade smaller positions at higher frequency.

Some observers argue sportsbooks could face increasing competition from prediction markets as sports-event volume grows. Reports noted more than $545 million was wagered on Kalshi for the 2026 Masters alone.

Legal uncertainty remains part of the sector outlook. One supplied report said a future U.S. Supreme Court decision may determine whether states hold authority over prediction markets or whether federal jurisdiction applies.