Prediction markets have continued their explosive growth, with March 2026 delivering $25.7 billion in notional volume, making it the second-highest month on record, according to data compiled by Dune Analytics. This figure trails only January's all-time high of $26.75 billion, signaling sustained demand for event-based trading instruments.
Polymarket and Kalshi Dominate the Landscape
The Dune dashboard, curated by @datadashboards, reveals that seven platforms contributed to March's volume, but two platforms—Kalshi and Polymarket—accounted for the lion's share. Kalshi recorded $13 billion in notional volume, while Polymarket reached $10 billion. Their combined share represents roughly 89.5% of the total market. Polymarket's traction is largely driven by political events, followed by cryptocurrency markets, sports, and global affairs. Kalshi's activity spans economics, finance, and politics, with expansion into niche areas such as climate, weather, and transportation.
Transaction counts underscore the two platforms' dominance. March saw approximately 207 million trades across all tracked prediction markets, up from 155 million in February. Polymarket processed 115 million transactions, while Kalshi handled 88 million, together accounting for over 98% of all trades. Smaller venues such as Crypto.com, Opinion, Limitless, Predict.fun, and Overtime.io registered only marginal activity.
Open Interest Nears $940 Million
As of writing, total open interest across prediction markets stands at approximately $939.86 million, with Kalshi leading at $487.21 million and Polymarket at $422.09 million. The remaining platforms hold negligible positions: Predict.fun has $19.51 million, Opinion $10.38 million, Limitless roughly $666,520, and others combined just $3,760. This highly concentrated market structure reflects the network effects and liquidity advantages enjoyed by the top two players.
Regulatory Headwinds Fail to Deter Growth
Despite the booming activity, Polymarket and Kalshi continue to face significant regulatory challenges. The Commodity Futures Trading Commission (CFTC) has maintained a cautious stance, while Democratic lawmakers have introduced legislation aimed at increasing oversight of prediction markets. Recently, California Governor Gavin Newsom signed an executive order prohibiting gubernatorial appointees from using insider information to place bets on prediction platforms. Additionally, markets related to the U.S.-Iran conflict have sparked public controversy.
Nevertheless, open interest and notional volumes continue to climb. Analysts note that prediction markets have evolved from experimental niche products into mature financial tools that provide real-time information aggregation. The durability of this momentum will depend on how platforms navigate the evolving regulatory landscape, but for now, Polymarket and Kalshi have firmly cemented their positions as market leaders.