On August 23, 2026, VolRoc recorded 254,892 active prediction markets across Kalshi and Polymarket, holding $1.84B in combined open interest. Day over day, active markets rose 2.7% and open interest fell 1.0% (vs August 22, 2026). Politics & Elections was the largest domain by open interest (31%), ahead of Sports (23%); together they accounted for 54% of all open interest. Kalshi carried 78% of active markets and Polymarket 22%.
Deterministic · template v1 · 2026-08-23
As of 2026-08-23 · 00:00 UTC
Active Markets
254,892
00:00 UTC freeze
Open Interest
$1.84B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
23,754
with trading activity
Kalshi / Polymarket
78% / 22%
by active-market count
Domain Composition — 12 domains
Mixed / Multi-category
161,666
Other
36,163
Sports
35,403
Politics & Elections
10,194
Entertainment & Culture
3,065
Crypto & Digital Assets
1,912
Technology & AI
1,752
Climate & Weather
1,355
Economics & Inflation
1,000
Companies & Business
910
World & Geopolitics
883
Monetary Policy
481
Science & Health
108
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 = 254,892.
Largest Kalshi Series
Cross-category multi-markets
161,666
—
3,027
Midterm control
1,141
Music — artist streams
771
U.S. House races
612
Sports — multi-game parlays
577
Nextteamnba
508
Primary vote shares
356
Nflwins
352
Nflspread
321
Ncaafwins
288
Mlbhr
265
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 23, 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 23, 2026.” https://volroc.ai/prediction-markets/2026-08-23/
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