On August 1, 2026, VolRoc recorded 209,020 active prediction markets across Kalshi and Polymarket, holding $1.65B in combined open interest. Day over day, active markets rose 40.8% and open interest rose 13.4% (vs July 31, 2026). Sports was the largest domain by open interest (47%), ahead of Politics & Elections (29%); together they accounted for 77% of all open interest. Kalshi carried 87% of active markets and Polymarket 13%.
Deterministic · template v1 · 2026-08-01
As of 2026-08-01 · 00:00 UTC
Active Markets
209,020
00:00 UTC freeze
Open Interest
$1.65B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
17,610
with trading activity
Kalshi / Polymarket
87% / 13%
by active-market count
Domain Composition — 12 domains
Sports
145,919
Mixed / Multi-category
26,712
Other
21,829
Politics & Elections
6,443
Entertainment & Culture
2,642
Crypto & Digital Assets
1,448
Companies & Business
1,026
Technology & AI
1,010
Economics & Inflation
919
Monetary Policy
382
World & Geopolitics
375
Climate & Weather
231
Science & Health
84
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 = 209,020.
Largest Kalshi Series
Sports — multi-game parlays
125,667
Cross-category multi-markets
26,712
Midterm control
948
Music — artist streams
752
U.S. House races
603
Nextteamnba
484
Mlbhr
271
Nflwins
271
NFL — next team moves
257
Nextteammlb
238
Flprimary
204
Mlbhit
198
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 1, 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 1, 2026.” https://volroc.ai/prediction-markets/2026-08-01/
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