On August 26, 2026, VolRoc recorded 234,142 active prediction markets across Kalshi and Polymarket, holding $1.77B in combined open interest. Day over day, active markets rose 24.0% and open interest rose 5.2% (vs August 25, 2026). Politics & Elections was the largest domain by open interest (30%), ahead of Sports (21%); together they accounted for 51% of all open interest. Kalshi carried 75% of active markets and Polymarket 25%.
Deterministic · template v1 · 2026-08-26
As of 2026-08-26 · 00:00 UTC
Active Markets
234,142
00:00 UTC freeze
Open Interest
$1.77B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
24,904
with trading activity
Kalshi / Polymarket
75% / 25%
by active-market count
Domain Composition — 12 domains
Mixed / Multi-category
139,807
Other
36,810
Sports
35,507
Politics & Elections
10,394
Entertainment & Culture
2,944
Crypto & Digital Assets
1,938
Technology & AI
1,761
Climate & Weather
1,386
Companies & Business
1,042
Economics & Inflation
1,011
World & Geopolitics
899
Monetary Policy
517
Science & Health
126
Venue-agnostic subject taxonomy from Kalshi series prefixes and
Polymarket title keywords. A residual Other bucket is reported honestly.
Yes-price across both venues, 10 buckets from 0 to 100. n = 234,142.
Largest Kalshi Series
Cross-category multi-markets
139,807
—
2,779
Midterm control
1,185
Music — artist streams
764
U.S. House races
614
Nextteamnba
508
Nflspread
366
Nflwins
357
Primary vote shares
350
Ncaafwins
310
Mlbhrr
297
Mlbhr
281
Kalshi market families (Polymarket is not series-structured).
About & Citation
This is the fixed-hour (00:00 UTC) state of every active market on
Kalshi and Polymarket for August 26, 2026. The live
Observatory
shows the current diurnal value; this record is immutable. Open interest combines Kalshi
open interest with Polymarket USD liquidity as comparable USD magnitudes. Sources: Kalshi, Polymarket.
How to cite
“VolRoc Prediction Market Archive — August 26, 2026.” https://volroc.ai/prediction-markets/2026-08-26/
Get the daily statistics
A short daily read on the prediction-market universe across Kalshi and Polymarket.
Join the list →