On August 22, 2026, VolRoc recorded 248,103 active prediction markets across Kalshi and Polymarket, holding $1.86B in combined open interest. Day over day, active markets rose 37.3% and open interest rose 13.0% (vs August 21, 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 · 2026-08-22
As of 2026-08-22 · 00:00 UTC
Active Markets
248,103
00:00 UTC freeze
Open Interest
$1.86B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
25,077
with trading activity
Kalshi / Polymarket
78% / 22%
by active-market count
Domain Composition — 12 domains
Mixed / Multi-category
154,418
Sports
36,204
Other
36,077
Politics & Elections
10,145
Entertainment & Culture
3,015
Crypto & Digital Assets
2,001
Technology & AI
1,733
Climate & Weather
1,173
Economics & Inflation
983
Companies & Business
892
World & Geopolitics
875
Monetary Policy
479
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 = 248,103.
Largest Kalshi Series
Cross-category multi-markets
154,418
—
3,868
Sports — multi-game parlays
1,698
Midterm control
1,138
Music — artist streams
767
U.S. House races
612
Nextteamnba
508
Nflspread
426
Primary vote shares
355
Nflwins
352
Nfltotal
290
Ncaafwins
285
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 22, 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 22, 2026.” https://volroc.ai/prediction-markets/2026-08-22/
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