On August 4, 2026, VolRoc recorded 145,756 active prediction markets across Kalshi and Polymarket, holding $1.28B in combined open interest. Day over day, active markets rose 61.6% and open interest rose 13.9% (vs August 3, 2026). Politics & Elections was the largest domain by open interest (38%), ahead of Sports (34%); together they accounted for 72% of all open interest. Kalshi carried 85% of active markets and Polymarket 15%.
Deterministic · template v1 · 2026-08-04
As of 2026-08-04 · 00:00 UTC
Active Markets
145,756
00:00 UTC freeze
Open Interest
$1.28B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
15,897
with trading activity
Kalshi / Polymarket
85% / 15%
by active-market count
Domain Composition — 12 domains
Sports
87,745
Mixed / Multi-category
24,760
Other
18,878
Politics & Elections
6,296
Entertainment & Culture
2,608
Crypto & Digital Assets
1,417
Companies & Business
1,048
Technology & AI
985
Economics & Inflation
981
Monetary Policy
387
World & Geopolitics
372
Climate & Weather
203
Science & Health
76
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 = 145,756.
Largest Kalshi Series
Sports — multi-game parlays
71,521
Cross-category multi-markets
24,760
Midterm control
956
Music — artist streams
746
U.S. House races
605
Nextteamnba
488
Nflwins
278
NFL — next team moves
257
Flprimary
206
Nextteammlb
200
Joinclub
198
Ncaafwins
182
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 4, 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 4, 2026.” https://volroc.ai/prediction-markets/2026-08-04/
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