The final March numbers are in, and they confirm what the mid-month trajectory suggested: March 2026 was the biggest month on record for U.S. prediction markets. Kalshi closed at $13.07 billion in notional volume and 88.4 million transactions, up 25% month-over-month on both metrics. Polymarket finished at $10.57 billion (+33% MoM) and 115.4 million transactions (+43% MoM), marking the second consecutive month both platforms set all-time highs simultaneously.
The final week of March told a more complicated story. Kalshi nudged higher to $2.90 billion (+6.4% week-over-week) on the strength of the NCAA Men’s Final Four, while Polymarket fell sharply to $1.97 billion (-12.0% WoW), its softest week since Feb. 16-22 when it was $1.82 billion. The divergence came down largely to category exposure: Polymarket’s crypto markets dropped 24%, while Kalshi’s politics category surged 36% WoW on government shutdown and Trump Cabinet shakeups. Kalshi is still down from its all-time high $3.40B peak in the week of March 16, which encompassed a high volume of 52 NCAA men’s basketball tournament games covering the First Four plus Round 1 and 2 games.
Kalshi vs. Polymarket MoM (October-March)
| Month | Kalshi Volume ($) | Polymarket Volume ($) | Kalshi Transactions | Polymarket Transactions |
|---|---|---|---|---|
| Oct 2025 | $4.40B | $4.10B | 16.4M | 12.1M |
| Nov 2025 | $5.81B | $4.33B | 22.1M | 18.6M |
| Dec 2025 | $6.58B | $5.31B | 29.8M | 30.2M |
| Jan 2026 | $9.55B | $7.66B | 54.5M | 52.0M |
| Feb 2026 | $10.44B | $7.94B | 70.8M | 80.7M |
| Mar 2026 | $13.07B | $10.57B | 88.4M | 115.4M |
Kalshi’s record month built on March Madness
Kalshi’s March record was fundamentally an NCAA tournament story, as previously documented. Sports, including its Exotics category, accounted for 82.5% of weekly volume in the final week, a concentration that has held remarkably steady throughout the tournament run. The platform’s single largest week of the period, the $3.40 billion record set during the March 16 week, came on the back of Selection Sunday and the tournament’s opening rounds. The Final Four, while carrying just two games, still pushed sports volume up 6.8% WoW, a sign of how much betting intensity concentrates in marquee matchups.
Kalshi’s dollar lead over Polymarket in notional volume has grown from $294 million in October to approximately $2.5 billion, a number that has held steady over the past two months even as Polymarket’s growth rate outpaced Kalshi’s in March. Kalshi captured 55.3% of combined K+P notional volume for the month, down slightly from 56.8% in February, but its dominance in high-profile sports markets remains the defining competitive advantage.
The non-sports picture is developing, if slowly. Politics reached 2.0% of Kalshi’s weekly mix, a modest share, but the +36% WoW jump in dollar terms shows there’s real user appetite for political markets when the news warrants it. Crypto held at 9.7% for a moderate decline. Everything else remains in rounding-error territory relative to sports.
Kalshi week over week category breakdown
| Category | Mar 23-29 | % of Total | Mar 30-April 5 | % of Total |
|---|---|---|---|---|
| Sports (incl. Exotics) | $2.24B | 82.2% | $2.40B | 82.5% |
| Crypto | $294M | 10.8% | $283M | 9.7% |
| Politics (incl. Elections) | $43M | 1.6% | $58M | 2.0% |
| Economy | $17M | 0.6% | $20M | 0.7% |
| Climate/Weather | $20M | 0.7% | $16M | 0.5% |
| Culture/Entertainment | $9M | 0.3% | $8M | 0.3% |
Polymarket hits record transactions, volume drops on crypto
Polymarket’s March growth numbers are genuinely strong as its 33% volume growth and 43% transaction growth both outpaced Kalshi, but the final week introduced a vulnerability worth watching. The platform’s crypto category dropped $161 million in a single week (-24% WoW), potentially reflecting the current broader crypto market downturn and regulatory uncertainty. Crypto represented 29.7% of Polymarket’s weekly mix the week prior; by the final week, that had compressed to 25.6%.
| Category | Mar 23-29 | % of Total | Mar 30-April 5 | % of Total |
|---|---|---|---|---|
| Sports | $861M | 38.4% | $834M | 42.3% |
| Crypto | $666M | 29.7% | $504M | 25.6% |
| Politics (incl. Trump) | $577M | 25.7% | $531M | 26.9% |
| Culture/Entertainment | $46M | 2.0% | $32M | 1.6% |
| Climate/Weather | $45M | 2.0% | $39M | 2.0% |
| Economy | $27M | 1.2% | $22M | 1.1% |
Polymarket’s politics category, meanwhile, is showing strong resilience. Politics, including Trump markets, held fairly steady at 26.9% of weekly volume even as total platform volume fell, and the Trump sub-category specifically grew WoW. Polymarket’s more diversified category mix is a strategic asset in politically active periods, though the crypto drop reveals a potential vulnerability tied to crypto sentiment shifts.
Transaction volume is Polymarket’s clearest structural strength. At 115.4 million transactions in March, 31% more than Kalshi, Polymarket is processing more trades by a wide margin, with an average trade size now around $92 versus Kalshi’s $148. As noted in prior reports, average trade sizes on both platforms have stabilized after compressing sharply since October, suggesting the user mix has found a new equilibrium rather than continuing to skew smaller. This of course could change in the near future, especially for Kalshi, as institutional traders ramp up participation.
Kalshi vs. Polymarket: Six week trend
Zooming out across the previous six-week window, the competitive picture has been consistent in direction but uneven in pace. Kalshi held a notional volume lead every single week, and that lead has widened considerably, from $329 million in the week of Feb. 23 to $932 million in the final week of March.
Kalshi vs. Polymarket volume and transactions (Six weeks through April 5)
| Week | Kalshi Volume ($) | Polymarket Volume ($) | Kalshi Transactions | Polymarket Transactions |
|---|---|---|---|---|
| 2026-02-23 | $2.73B | $2.40B | 18.7M | 24.6M |
| 2026-03-02 | $2.86B | $2.50B | 20.0M | 26.3M |
| 2026-03-09 | $2.93B | $2.34B | 19.7M | 24.7M |
| 2026-03-16 | $3.40B | $2.54B | 21.4M | 27.4M |
| 2026-03-23 | $2.73B | $2.24B | 19.0M | 26.3M |
| 2026-03-30 | $2.90B | $1.97B | 20.1M | 22.7M |
The pattern shows two distinct dynamics. When the sports calendar is heavy with conference championships and the early tournament rounds, Kalshi pulls away. When volume normalizes, as it did the week of March 23, the gap compresses. The final week’s $932 million lead is something of an outlier, amplified by Polymarket’s crypto-related pullback rather than any outsized Kalshi surge.
On transactions, the story flips. Polymarket led every week in the dataset, processing between 3 and 6 million more trades than Kalshi each week. That lead narrowed sharply in the March 30 week to just 2.6 million, the closest the platforms have been in the tracking window, again driven more by Polymarket’s volume drop than by Kalshi closing the gap organically.
The rest of the field
Outside the top two, Crypto.com was the standout in March, posting $629 million, its strongest month yet and a 58.5% jump from February. It’s building toward a consistent third-place position and bears watching as it adds volume.
Limitless had a rougher close to the month, falling every week through March after peaking at $145 million in the March 2 week, and dropping 52% in the final week alone to $33 million. predict.fun pulled back sharply (-58% MoM to $330 million) after a strong February, and Opinion continued its structural retreat, down 84% from its January peak to $496 million, seemingly settling into a much smaller footprint after the event-driven volume that fueled its earlier surge dissipated.
What’s ahead
The NCAA Men’s Championship game Monday night falls within the current week’s data window, which should deliver a meaningful volume spike, particularly on Kalshi, which has consistently captured the majority of high-profile college basketball action. The National Championship winner market, a futures market that has been accumulating volume since it opened on Oct. 28, has amassed around $230 million in trading volume as of Monday morning.
Beyond the title game, April brings the full ramp of NHL playoffs, the MLB regular season and the Masters Tournament, which kicks off April 9. Golf majors have historically generated high prediction market volume, and upcoming PGA majors will be no exception.
Macro and political markets also aren’t going anywhere. Trump moves and political drama have already shown they can meaningfully move platform volume week-to-week, and the policy calendar stays full through spring.
The regulatory backdrop also shifted this week. On April 3, a Nevada judge extended the ban on Kalshi operating in the state. One day earlier, the CFTC filed lawsuits against three states challenging their authority to regulate platforms like Kalshi. The federal-versus-state regulatory battle is now in active litigation, an overhang for the industry that could shape market access and platform strategy well into 2026 and beyond.
March set the ceiling. April will tell us whether it’s a floor to grow from.
Note: Data from our internal prediction markets tracking and Dune data dashboards contributed to this report.
