Kalshi Hits Record $3.4B Week, Polymarket Sports Surge as March Madness Heats Up

The numbers prediction market watchers had been anticipating since Selection Sunday lastly arrived final week. Prediction market business notional quantity hit $6.41 billion for the week of March 16–22, a brand new all-time high within the DeFi Rate monitoring interval, pushed by back-to-back report weeks from Kalshi and a significant surge from Polymarket as Round 1 of the NCAA Tournament tipped off Thursday. The prior mixed report, set two weeks earlier, was $5.89 billion.

Kalshi posted $3.40 billion in notional quantity, breaking its personal single-week report of $2.93 billion set the week prior. Polymarket added $2.54 billion, up 8.5% week-over-week. Together the 2 platforms generated $5.94 billion, the very best mixed weekly whole on report. What makes this week totally different from prior data is that each platforms grew concurrently, in lockstep with the sports activities calendar (week one among March Madness).

As our dwell prediction markets tracker exhibits, lively markets exploded week over week from 309,969 to 455,631 (+145,662 / +47.0%), nearly solely from Kalshi constructing out its March Madness markets, shifting from 274,857 to 419,953 (+145,096).

Kalshi pulling away from Polymarket on sports activities quantity

Kalshi held 57.2% market share on a head-to-head foundation, up from 55.6% the prior week. The hole is widest throughout main sports activities occasions, and this week was as sports-heavy as any week exterior the Super Bowl.

The extra attention-grabbing metric is open curiosity, which moved from $870.0M → $952.0M (+$82.0M / +9.4%) based mostly on our monitoring. Kalshi drove the majority of it: $428.8M → $497.0M (+$68.2M), as merchants loaded into each particular person sport contracts and event futures with the beginning of the NCAA basketball tournaments. Polymarket was comparatively flat, $440.1M → $447.8M (+$7.7M). Polymarket US jumped from $1.1M to $8.2M, a small absolute quantity however a 6.5x transfer, reflecting sports activities buying and selling ramping up on the US platform, due to NCAA event betting curiosity.

Kalshi surges on March Madness, Polymarket stays regular

Kalshi’s sports activities quantity jumped 27.5% week-over-week to $2.67 billion, pushing its sports activities focus from 71.3% to 78.6% — the very best share for the reason that NFL playoff weeks in January. The driver is simple: the NCAA Tournament is the one occasion on the sports activities calendar that constantly rivals Super Bowl week in each market rely and per-game buying and selling exercise, and this yr’s event delivered instantly.

Round 1 video games dominated Kalshi’s high markets for the week. Among the highest-volume matchups: Vanderbilt at Nebraska ($9.9M), Texas at Gonzaga ($7.5M), High Point at Arkansas ($7.5M), Louisville at Michigan State ($7.3M), and TCU at Duke ($6.9M). For context, the highest Round 1 sport on Kalshi drew extra quantity than any single sport within the platform’s weekly high 10 simply two weeks in the past, when convention event video games had been thought-about a milestone. Kalshi additionally gives unfold and whole factors markets alongside moneylines for every sport — Texas at Gonzaga: Spread drew $1.7M individually, and TCU at Duke: Spread added one other $3.2M — which means per-matchup quantity is meaningfully greater than any single contract suggests.

The futures market tells the longer story. Kalshi’s Men’s College Basketball Champion market has accrued $91.4 million in open curiosity, with Michigan (21%), Arizona (20%), and Duke (18%) main. That OI determine, bigger than any single weekly top-10 market, displays merchants with positions that run by means of April 7.

Beyond sports activities, Kalshi’s Crypto class grew 22.1% week-over-week to $285.3M, and Politics was up 30.3% to $25.0M. The Entertainment class collapsed 87.8% to $7.6M, which was solely anticipated, as the prior week captured Oscars Sunday buying and selling quantity that has now settled off the board.

Kalshi’s Unknown class dropped 62.2% to $72.8M, which may very well be from Dune Analytics reclassifying newly created event contracts into the Sports class as matchups had been confirmed after bracket launch.

Polymarket: Sports approaches parity with non-sports for the primary time

Polymarket’s $2.54 billion week was pushed by a rotation that doesn’t present up clearly within the top-line quantity. Sports quantity surged 32.2% to $1.22 billion, its largest weekly sports activities whole within the monitoring interval, pushing sports activities focus from 39.5% to 48.1%. That’s the closest Polymarket has come to a 50/50 sports activities/non-sports break up since we started monitoring class knowledge.

The NCAA Tournament was the catalyst on Polymarket too, although at a smaller scale than Kalshi. The platforms’ high NCAA markets overlapped in groups however not in contract construction: the place Kalshi runs per-game moneylines and spreads, Polymarket’s highest-volume event marketplace for the week was the 2026 NCAA Tournament Winner futures contract ($2.1M weekly, $980K OI), with Arizona and Michigan co-leading at 20% every, Duke at 17%. Individual sport moneylines on Polymarket additionally drew quantity — VCU vs. Illinois ($4.1M) and Texas vs. Gonzaga ($3.1M) had been each within the cross-platform high 30 — however Polymarket’s game-level quantity runs at a fraction of Kalshi’s for comparable matchups.

The extra attention-grabbing story on Polymarket is what didn’t occur to politics. Politics and Trump mixed fell 11.6% to $594.7M — an actual decline in an in any other case up week. The Fed’s March price choice, which topped Polymarket’s leaderboard final week at $141.9M, has now resolved. What’s changing it’s 2028 presidential positioning: the Republican Presidential Nominee 2028 market led Polymarket’s 7-day quantity at $11.6M (J.D. Vance at 37%, Marco Rubio at 27%), and the Democratic Presidential Nominee 2028 market adopted at $8.9M (Gavin Newsom at 25%). Both carry substantial open curiosity — $14.1M and $10.1M respectively — indicating these aren’t short-term occasion trades however positions merchants are holding by means of the cycle. The 2028 Presidential Election market added one other $2.8M in weekly quantity with $35.0M in OI, the most important open curiosity determine on the board.

Culture dropped 47.1% — once more, Oscars impact. Crypto was primarily flat at $635.7M (+1.6%), sustaining its place as Polymarket’s second-largest class behind Sports.

Polymarket nonetheless dominates by way of non-sports quantity, which is now bigger than Kalshi’s non-sports quantity by nearly 2x: $1.34B versus $726M. As famous in earlier reviews, the 2 platforms are serving meaningfully totally different dealer populations at this level. Kalshi is operating 78.6% sports activities this week, whereas Polymarket is operating 51.9% non-sports.

Full platform comparability

Total business quantity throughout all Dune-tracked platforms reached $6.41B for the week of March 16–22, up 11.4% from $5.76B the prior week. Kalshi and Polymarket mixed accounted for 93.4% of whole tracked quantity, persevering with the consolidation development that has characterised the previous two months.

Opinion Markets rebounded 65.0% to $128.5M after 5 consecutive weeks of decline. It’s price noting, although, it stays far beneath its $1.81B peak from late December and the bounce could also be noise moderately than a development reversal. Crypto.com held regular at $158.7M (+1.6%). Limitless fell 23.2% to $98.5M and predict.enjoyable declined 33.8% to $60.3M.

On transactions, Polymarket maintained its lead with 27.4M versus Kalshi’s 21.4M, a 56/44 break up that has been constant for months. Total business transactions hit 49.6M throughout all tracked platforms, up 9.7% week-over-week.

Note: Comparing smaller platforms over time isn’t absolutely dependable given how Dune teams sure platforms — Limitless, Myriad, and ForecastEx have been consolidated below “Other” at numerous factors within the monitoring interval. Week-over-week modifications for these platforms ought to be handled as directional moderately than exact.

Polymarket US check-in

Polymarket US generated $5.9M in weekly notional quantity, flat versus the prior week regardless of the NCAA Tournament launch. The platform added 108 lively markets to achieve 596, with Round 1 sport traces now accessible — however particular person contract quantity stays within the low 5 figures for many video games. Texas at Gonzaga drew $182.6K on Polymarket US; the identical sport did $7.5M on world Polymarket and way more on Kalshi.

Open curiosity grew meaningfully to $8.2M, up from $1.1M the week prior, as NCAA event futures accrued. The quantity ceiling for particular person US-market contracts hasn’t shifted but, however the OI development suggests merchants are taking positions moderately than simply watching.

What comes subsequent

The Round of 32 runs by means of Sunday, March 22, and the Sweet 16 suggestions off Thursday, March 27. Based on Kalshi’s convention event efficiency two weeks in the past, the place particular person video games drew $7-10M, Round of 32 matchups involving main packages might simply clear these ranges. The video games with probably the most quantity potential are those pitting high-seeded packages with massive nationwide fanbases towards credible upset threats. Duke ($6.9M in Round 1 on Kalshi), Michigan ($5.4M), and Texas ($7.5M) are the early indicators of the place dealer consideration is concentrated. The Men’s College Basketball Champion futures market at $91.4M in OI will proceed to cost in real-time as the bracket tightens.

Longer-term, the query is what Kalshi’s quantity trajectory seems like after the event ends in early April. The platform has now set back-to-back weekly quantity data through the faculty basketball calendar, following a sample established through the NFL season. Whether that interprets to sustained $3B+ weeks through the NBA playoffs alone, with out the event’s per-game quantity density, is the goal quantity to observe in Q2.

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