Kalshi and Polymarket Global combined for $16.43 billion in contract volume during the week of Sept. 14-20, a 16.3% increase from the prior week. For a second consecutive week, NFL and college football sat at the center of the action, alongside the Federal Reserve’s interest rate decision and a busy slate of international elections.
Kalshi accounted for the overwhelming majority of that total. It recorded $15.27 billion in volume, its highest-volume week of 2026, translating to $3.53 billion in execution-price USD across 85.26 million trades. The week also included Kalshi’s first $3 billion trading day. Sports accounted for $3.24 billion of activity, with football markets featuring prominently among the week’s busiest.
Top-line performance notes
- Kalshi: Displayed contract volume reached $15.27 billion, translating to $3.53 billion in execution-price USD across 85.26 million trades. Kalshi accounted for 92.9% of the combined contract volume between itself and Polymarket Global.
- Sports: Sports accounted for $3.24 billion in volume on Kalshi, with NFL and college football markets among the biggest sources of activity during the week.
- Crypto: Kalshi generated $2.16 billion in crypto contract volume, far ahead of Polymarket Global’s $188.00 million and making Kalshi the dominant platform in the category.
Kalshi’s first $3 billion day
Kalshi also recorded its first $3 billion day, with $3.17 billion in contract volume on Sept. 20. The previous day, Sept. 19, produced $2.81 billion. Those were the two highest-volume days on Kalshi so far in 2026.
These were the 10 largest markets of the $3 billion day, with game markets combined across their winner outcomes to match the rest of this report:
| Rank | Market | Contract volume |
|---|---|---|
| 1 | Cross-category combo (10 legs) | $44.11 million |
| 2 | LSU vs Ole Miss | $38.62 million |
| 3 | UFC: Van vs Pantoja | $18.00 million |
| 4 | Las Vegas Raiders vs Los Angeles Chargers | $17.02 million |
| 5 | Philadelphia Eagles vs Tennessee Titans | $16.37 million |
| 6 | Green Bay Packers vs New York Jets | $16.03 million |
| 7 | Atlético Madrid vs Real Madrid | $14.68 million |
| 8 | Jacksonville Jaguars vs Denver Broncos | $14.58 million |
| 9 | Washington Commanders vs Dallas Cowboys | $13.77 million |
| 10 | Minnesota Vikings vs Chicago Bears | $12.87 million |
Those 10 markets accounted for $206.06 million, or 6.5% of the day’s volume. The remainder came from a long tail of game, player-prop and combo markets across the exchange.
A major trend behind Kalshi’s volume growth was the continued expansion of cross-category multi-leg “Combo” markets. Mapped combo volume on Kalshi reached $2.39 billion.
- The largest individual Kalshi market in the weekly dataset was a 10-leg NFL combo spanning Carolina, Cincinnati, Tampa Bay, New York (Jets), Jacksonville, Las Vegas and four more teams. It generated $71.49 million in contract volume.
- Other major Kalshi combos included a multi-team MLB baseball combo ($39.49 million), an English Premier League soccer combo ($33.24 million), and an MLB total runs combo ($30.03 million).
Kalshi holds 92% of combined crypto volume
Crypto was another major source of activity for Kalshi during the week, with the platform generating $2.16 billion in contract volume.
- Crypto: Kalshi recorded $2.16 billion in crypto volume, compared with $188.00 million on Polymarket Global.
- Kalshi’s crypto volume was more than 11 times the amount recorded by Polymarket Global, giving it a clear lead in the category.
- Overall crypto category volume across Kalshi and Polymarket reached $2.34 billion, with Kalshi accounting for 92% of the total.
Kalshi Crypto Market Growth
| Month | Kalshi crypto volume ($) | Polymarket Global crypto volume ($) |
|---|---|---|
| Jan 2026 | 336.7M | 1.8B |
| Feb 2026 | 790.5M | 2.4B |
| Mar 2026 | 1.2B | 2.9B |
| Apr 2026 | 1.4B | 1.9B |
| May 2026 | 2.0B | 1.3B |
| Jun 2026 | 4.0B | 1.3B |
| Jul 2026 | 6.3B | 1.2B |
| Aug 2026 | 7.5B | 862.3M |
| Sept 2026 (partial, Sept 1-20) | 5.5B | 522.2M |
More NFL and college football … shocker!
NFL and college football were among the biggest sources of market activity on Kalshi. Sports accounted for $3.24 billion in volume, with several individual NFL and college football matchups generating tens of millions of dollars in contract volume.
These were some of the top sources of activity:
- Detroit Lions vs. Buffalo Bills: Contract volume on Kalshi reached $46.03 million.
- LSU vs. Ole Miss: Generated $49.60 million on Kalshi.
- Denver Broncos vs. Kansas City Chiefs: Recorded $47.06 million on Kalshi.
Kalshi’s volume by market category
The record week did not come from one part of the exchange. Cross-category combo markets, which bundle legs from different categories into a single contract, were the largest slice by a wide margin, ahead of football and crypto combined. That is also why the biggest slice in the chart below carries an uncategorized label, since those bundled contracts sit outside Kalshi’s single-category buckets.
Take the combos out and the week looks more familiar. Sports volume spread across dozens of individual games and player props, crypto activity concentrated in Bitcoin and Ether markets, and everything else, from financial and economic markets to politics and weather, stayed small against a record total.
Looking ahead: Events to watch Sept. 21-27
- NFL football markets should remain one of the biggest sources of prediction-market activity on Kalshi. The schedule includes Falcons-Packers on Thursday night, Cowboys-Ravens in the NFL’s Rio de Janeiro international game, Rams-Broncos on Sunday night. The full Sunday slate also includes Chargers-Bills, Jets-Lions, Chiefs-Dolphins and Bengals-Steelers, with Eagles-Bears closing the week next Monday, Sept. 28.
- College football enters another important weekend, with conference play providing a steady stream of game and player-prop markets and a total of six ranked matchups.
- The Federal Reserve will remain a major source of economic-market activity even after its September rate decision. Fed officials have several appearances scheduled this week, including Vice Chair Philip Jefferson on Tuesday and Governor Michael Barr on Wednesday. More economic data, including September PMI figures, jobless claims, new home sales, and durable-goods orders, could also create new markets around the economy and future Fed policy.
- Crypto should remain another major source of Kalshi activity following the category’s massive $2.16 billion week.
- Baseball will enter the final stretch of the MLB regular season, with playoff races creating additional markets around division winners, wild cards, and individual games. The regular season continues through Sept. 27, giving Kalshi another week of increasingly consequential baseball markets.
