On July 26, 2026, VolRoc recorded 187,274 active prediction markets across Kalshi and Polymarket, holding $1.62B in combined open interest. Day over day, active markets fell 20.4% and open interest fell 10.1% (vs July 25, 2026). Sports was the largest domain by open interest (44%), ahead of Politics & Elections (30%); together they accounted for 74% of all open interest. Kalshi carried 78% of active markets and Polymarket 22%.
Deterministic · template v1 · 2026-07-26
As of 2026-07-26 · 00:00 UTC
Active Markets
187,274
00:00 UTC freeze
Open Interest
$1.62B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
20,294
with trading activity
Kalshi / Polymarket
78% / 22%
by active-market count
Domain Composition — 12 domains
Sports
123,312
Other
27,938
Mixed / Multi-category
18,998
Politics & Elections
6,716
Entertainment & Culture
2,755
Crypto & Digital Assets
1,841
Companies & Business
1,413
Technology & AI
1,197
Climate & Weather
1,176
Economics & Inflation
921
World & Geopolitics
462
Monetary Policy
460
Science & Health
85
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 = 187,274.
Largest Kalshi Series
Sports — multi-game parlays
98,201
Cross-category multi-markets
18,998
Midterm control
905
Music — artist streams
768
U.S. House races
597
Nextteamnba
482
NFL — next team moves
255
Mlbhr
247
Nflwins
239
Nextteammlb
231
Mlbhit
202
Flprimary
195
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 July 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 — July 26, 2026.” https://volroc.ai/prediction-markets/2026-07-26/
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