Follow the money.
Prediction market volume, trading fees and retained revenue. Core comparable venues plus expanded exchange coverage.
Fees are not total company revenue. Fee coverage excludes Kalshi; retained revenue covers Polymarket International only. No industry-wide revenue total is implied.
Where the activity is
| KalshiUS exchange | $13.52BSource-tracked | 74.6% | +18.5% | UnavailableNo validated current feed | UnavailableNo validated current feed |
|---|---|---|---|---|---|
| Polymarket USUS exchange | $2.48BSource-tracked | 13.7% | +55.0% | $62.26MSource estimate | UnavailableNo validated current feed |
| Polymarket InternationalInternational | $2.13BSource-tracked | 11.8% | -9.3% | $31.32MSource-tracked | $15.23MSource-tracked |
Scroll the table to compare every metric →
Monthly cash trading volume
Scroll chart to explore all 12 months ↔
View monthly figures
| Month | Kalshi | Polymarket International | Polymarket US |
|---|---|---|---|
| September 2026 | $13,522,743,056.00 | $2,133,496,027.00 | $2,480,530,361.00 |
| August 2026 | $11,411,504,027.00 | $2,351,297,208.00 | $1,600,738,954.00 |
| July 2026 | $12,368,578,641.00 | $3,656,908,378.00 | $2,016,081,645.00 |
| June 2026 | $9,395,285,762.00 | $4,277,925,294.00 | $1,656,715,338.00 |
| May 2026 | $6,151,194,189.00 | $3,228,242,018.00 | $718,241,828.00 |
| April 2026 | $5,374,409,814.00 | $4,147,210,662.00 | $445,162,317.00 |
| March 2026 | $5,260,827,119.00 | $4,788,960,123.00 | $297,503,622.00 |
| February 2026 | $4,157,617,050.00 | $3,551,935,847.00 | $125,396,716.00 |
| January 2026 | $3,718,952,168.00 | $3,394,311,584.00 | $131,675,010.00 |
| December 2025 | $2,681,067,131.00 | $2,275,608,929.00 | $42,212,143.00 |
| November 2025 | $2,576,065,119.00 | $1,878,764,903.00 | $1,227,901.72 |
| October 2025 | $1,987,358,665.00 | $1,508,222,759.00 | Unavailable / incomplete |
What Polymarket collects and retains
Scroll chart to explore all 12 months ↔
View monthly figures
| Month | International gross fees | US gross fees (estimated) | International retained revenue |
|---|---|---|---|
| September 2026 | $31,316,487.00 | $62,256,521.00 | $15,234,716.00 |
| August 2026 | $36,084,932.00 | $34,129,024.00 | $18,291,833.00 |
| July 2026 | $46,325,414.00 | $42,338,062.00 | $23,070,594.00 |
| June 2026 | $41,301,276.00 | $30,256,730.00 | $22,019,706.00 |
| May 2026 | $29,325,212.00 | $13,216,508.00 | $16,574,327.00 |
| April 2026 | $32,345,187.00 | $8,231,430.00 | $18,991,209.00 |
| March 2026 | $8,647,631.00 | $2,975,606.00 | $4,847,412.00 |
| February 2026 | $4,987,344.00 | $1,254,197.00 | $3,275,592.00 |
| January 2026 | $2,616,700.00 | Unavailable / incomplete | $45,344.00 |
| December 2025 | $0.00 | Unavailable / incomplete | $0.00 |
| November 2025 | $0.00 | Unavailable / incomplete | $0.00 |
| October 2025 | $0.00 | Unavailable / incomplete | $0.00 |
Kalshi accounts for 74.6% of tracked cash trading volume in September 2026. Its volume is 18.5% higher vs prior month.
Automatically calculated from the selected period. Share covers these three venues, not the entire prediction market industry.More prediction-market data sources
| Data through | Status | ||||||
|---|---|---|---|---|---|---|---|
| Novig ExchangeExchange | $1.45B30 published days | 4,211,101 | — | — | — | 2026-10-14 | Current2 daily rows refreshed |
Observed notional is shown only where the source publishes/imports it. Reported fees, estimated fees and retained revenue remain separate nullable fields. A blank value is not treated as zero.
Aldrin market-structure observations
These Aldrin observations are validation/context benchmarks, not replacements for source-native daily imports. Taker volume, notional and cash trading volume are different measures and are not summed together.
What is included
Volume
Cash traded is the transaction value in USD. Contract notional measures the payout face value traded. They are different measures; changing the selector changes volume and share together.
Fees & revenue
Gross fees measure trading charges. Retained protocol revenue deducts the rewards and rebates identified by the source. It is not audited company revenue or net profit.
Coverage & dates
Only complete periods receive totals. Missing values are never treated as zero. Today’s observations are excluded. Dates follow the provider’s reporting labels; Kalshi’s current adapter reads the prior day’s report, so daily trade timing may differ.
Sources, refresh times & methodology
Source: DefiLlama public daily-history APIs. Daily imports are scheduled for 08:00 UTC and subject to source availability and WordPress cron. This page uses stored observations from 2025 onward. Historical figures may be revised by the source. Cash and notional histories are imported separately; no fixed take rate is used to invent fees.
Polymarket International and Polymarket US are separate rows. The parent Polymarket total is excluded to prevent double counting; unrelated perpetual products are excluded. Kalshi fees and revenue, US retained revenue, and sports/category splits have no validated current feed in this version and are not inferred.
Polymarket US gross fees are calculated by the source from its fee schedule and trades, so they remain estimates. Monthly changes compare full calendar months; rolling windows compare equal-length preceding windows. Month-to-date comparisons use matching elapsed days, capped at the shorter month. Source accounting conventions and reporting lags may limit comparability.
- Kalshi · volume — Source-tracked. Data through 2026-10-14; fetched 2026-10-15T08:00:54+00:00.
- Kalshi · notional — Source-tracked. Data through 2026-10-14; fetched 2026-10-15T08:01:01+00:00.
- Polymarket International · volume — Source-tracked. Data through 2026-10-13; fetched 2026-10-15T08:01:11+00:00.
- Polymarket International · notional — Source-tracked. Data through 2026-10-13; fetched 2026-10-15T08:01:37+00:00.
- Polymarket International · fees — Source-tracked. Data through 2026-10-14; fetched 2026-10-15T08:01:48+00:00.
- Polymarket International · revenue — Source-tracked. Data through 2026-10-14; fetched 2026-10-15T08:01:53+00:00.
- Polymarket US · volume — Source-tracked. Data through 2026-10-14; fetched 2026-10-15T08:02:12+00:00.
- Polymarket US · notional — Source-tracked. Data through 2026-10-14; fetched 2026-10-15T08:02:40+00:00.
- Polymarket US · fees — Source estimate. Data through 2026-10-14; fetched 2026-10-15T08:02:42+00:00.
Kalshi volume adapter · International volume adapter · US volume and fee adapter · International fee and revenue adapter
Jason Ziernicki is the founder of CLEATZ and has worked in the online sports betting industry since 2012. At CLEATZ, he focuses on public betting data, sportsbook line movement, prediction markets and data-driven sports betting tools.
