How March Madness triggered a $25 million surge for Kalshi in a new betting wave

• The event contracts platform processed over $2 billion in transactions during the first four days of the NCAA tournament.

• Trading volume on March 19 ranked as the second busiest day in the company’s history, surpassed only by the last Super Bowl.

• College basketball dominated 90% of the total betting volume, establishing Kalshi as a major competitor against giants like BetMGM.

The March Madness phenomenon has proven to be much more than a sporting competition, transforming into an unprecedented financial engine for Kalshi. During the first two rounds of the 2026 NCAA men’s basketball tournament, the platform earned $25.5 million in fee revenue, a figure that exceeds what was collected in the first five months of the previous year. This surge not only reflects the passion for college sports but also the growing adoption of prediction markets as a regulated and dynamic alternative to traditional sportsbooks in the United States.

A transaction volume breaking records

The flow of capital during the opening weekend was massive, reaching a total volume of $2.34 billion in just four days. The first Thursday of the tournament recorded $645.7 million in transactions, becoming the second best day in Kalshi’s history. This frantic activity allowed the week ending March 23 to solidify as the company’s highest seven day volume period, exceeding $3.40 billion and generating total fees of $33.1 million.

College basketball’s dominance in betting

As expected, sports dictated the platform’s pace, accounting for 90% of the total processed volume. Specifically, direct college basketball bets made up more than half of the volume in the first round and nearly 40% in the second. A determining factor was the integration of Kalshi contracts into Robinhood’s “prediction center,” which facilitated access for thousands of retail users who injected $900 million in “taker” side bets during the tournament.

The Duke – Siena match: A case study

One of the most striking points of the weekend was the matchup between Duke and Siena, which attracted $42.4 million in revenue volume. The market was driven by restrictions in New York, which prohibit local sportsbooks from offering markets on in state college teams. Since Siena is a New York based team, residents turned their activity toward Kalshi. This match saw the largest single bet of the tournament: $990,000 in favor of Duke, a high risk position that was in jeopardy when Siena took a 13-point lead before the Blue Devils’ comeback.

Bettor performance and parlays

Despite the high volume, profitability for users was mixed and during the first round, participants faced losses of 5.25% on college basketball bets after fees. However, parlays offered more volatile but favorable results in certain stretches; after a difficult start on March 19, bettors achieved an 11.8% gain the following day thanks to unexpected outcomes. In total, users invested $430 million in individual games and another $45 million in parlays during this initial period.

Projections for a historic 2026

With the momentum from March Madness, Kalshi is on track to exceed $1 billion in fee revenue this year, having already crossed the $340 million mark. This exponential growth 12 times higher than what was recorded in the same rounds of 2025 places the company in a privileged position to challenge for the third spot in the United States sports betting market. Meanwhile, competitors like Polymarket US are also showing signs of expansion, reaching daily highs of $60.1 million, confirming that 2026 will be the definitive year for the consolidation of prediction markets.