Key Highlights
- The combined lifetime trading volume for Kalshi and Polymarket surpassed $150 billion during April 2025
- Kalshi achieved an all-time high of $14.81 billion in monthly volume, representing a 13.3% increase from March
- Polymarket experienced a 14.8% decline to $9.01 billion, expanding Kalshi’s competitive advantage to $5.8 billion
- Active user participation on Polymarket decreased from 733,000 traders in March to 643,000 in April
- Athletic events and exotic combination contracts account for approximately 85% of Kalshi’s trading volume
The prediction market industry achieved a significant benchmark in April as Kalshi and Polymarket collectively surpassed $150 billion in all-time trading volume. This achievement arrived despite the sector experiencing its first month-over-month decrease in trading activity following seven consecutive months of unprecedented expansion.
Kalshi emerged as the dominant force, recording $14.81 billion in notional trading volume throughout April. This figure represented a 13.3% surge compared to its prior monthly record of $13.07 billion established in March.
The achievement was particularly noteworthy given the timing. April lacked major sporting spectacles like the Super Bowl, March Madness tournament, or NFL postseason games. Instead, the month featured the commencement of NBA and NHL playoffs, The Masters championship, and the opening of Major League Baseball’s regular season.
The Masters tournament alone produced $545 million in notional trading volume on Kalshi — precisely matching the platform’s Super Bowl single-game volume of $545.1 million.
Polymarket experienced contrasting momentum. Its notional volume contracted by 14.8%, declining from $10.57 billion in March to $9.01 billion in April. This shift expanded Kalshi’s monthly advantage over Polymarket to $5.8 billion, significantly exceeding the $2.5 billion differential observed in March.
Athletic Events and Exotic Contracts Fuel Kalshi’s Momentum
Sports-related contracts comprised 74.3% of Kalshi’s weekly trading volume during the week ending April 20. When factoring in Exotics — the platform’s combination-style parlay contracts — this proportion approached approximately 85%.
Exotic contracts are experiencing rapid expansion. During the week of April 20, they generated $412.5 million, representing roughly 10.6% of Kalshi’s total weekly activity, up from 8.7% the previous week.
Kalshi’s taker volume in April reached $5.42 billion versus Polymarket’s $1.99 billion. Kalshi also executed more individual transactions — 94.4 million compared to Polymarket’s 87.4 million — reversing a longstanding pattern where Polymarket had maintained superiority in transaction volume.
Polymarket’s Diversified Portfolio Creates Mixed Results
Polymarket’s market composition differs substantially from Kalshi’s approach. During the week of April 20, sports contracts led at 46%, while cryptocurrency markets represented 22% and political forecasting markets contributed an additional 27%.
This diversification strategy serves Polymarket well during periods of heightened cryptocurrency enthusiasm or significant political developments. However, when both categories experience quiet periods — as occurred throughout portions of April — the platform lacks the sports-dominated foundation to maintain consistent volume.
Polymarket’s active participant count fell from exceeding 733,000 in March to approximately 643,000 in April. The reduction indicates that a portion of March’s engagement was attributable to March Madness, with April representing a more normalized user baseline.
Regarding regulatory developments, Polymarket is allegedly pursuing opportunities to introduce its international marketplace to U.S. users following the acquisition of a CFTC-licensed derivatives exchange. Kalshi secured additional funding in March at a $22 billion company valuation. Polymarket is purportedly attempting to raise capital at a $15 billion valuation.
Nine months prior, the prediction market industry was handling approximately $2 billion monthly. In April 2025, combined monthly volume across both leading platforms reached roughly $28 billion.
