Kalshi tops Polymarket as prediction markets hit $8.6B

Kalshi overtook Polymarket in April 2026 to become the largest prediction market by taker volume. Sector-wide taker trades totaled $8.6 billion in April, with Kalshi vs Polymarket reporting $5.42 billion and $1.99 billion, respectively, based on on-chain data tracked on Dune Analytics.

Monthly notional volume across the sector was $29.8 billion in April. Kalshi led notional volume with $14.8 billion. Polymarket recorded $9.0 billion in notional volume, plus an additional $1.26 billion from its U.S. product after re-entering the American market via the QCEX acquisition in late 2025.

Transaction counts for April totaled 184.3 million across the sector. Kalshi processed 94.4 million transactions and Polymarket handled 87.4 million. Polymarket drew 678,342 unique users in April, more than eight times Kalshi’s implied user base. Other platforms saw smaller user counts: Limitless had 71,203 users, predict.fun 18,553 and Opinion 3,423.

Open interest across prediction markets stood at $1.11 billion on May 1, 2026. Kalshi held $630.7 million of that open interest and Polymarket held $449.9 million. Predict.fun, Opinion and Limitless each carried well under $15 million in open positions.

Monthly fee revenue for the sector reached $31.15 million in April. Polymarket collected $29.22 million of that total. Limitless generated $1.51 million in fees, Predict $260,000 and Opinion $154,000. Polymarket accounted for the majority of fee revenue despite having lower taker volume than Kalshi for the month.

The prediction market model originated with 19th-century election betting and gained academic attention in 1988 with the Iowa Electronic Markets. Commercial prediction platforms emerged in the 2000s and blockchain-based experiments appeared in the 2010s. Polymarket launched in 2020 on Polygon and settled contracts in USDC. Kalshi received Commodity Futures Trading Commission approval as a Designated Contract Market in 2021.

Activity increased around the 2024 U.S. presidential election. Total industry volume for 2025 exceeded $63 billion. Monthly notional volume peaked near $25.7 billion in March 2026 before falling to April’s $29.8 billion notional and $8.6 billion in taker terms. Since mid-2024, monthly taker volume rose from below $500 million to multi-billion-dollar months, an expansion of roughly 17-fold.

Market concentration remains high. Kalshi and Polymarket are estimated to control between 85% and 95% of industry volume. In April, predict.fun recorded $579.2 million in taker volume, Opinion $376.2 million and Limitless $205 million; all other platforms combined accounted for about $12.2 million.