On July 8, 2026, VolRoc recorded 157,476 active prediction markets across Kalshi and Polymarket, holding $1.61B in combined open interest. Day over day, active markets rose 6.3% and open interest fell 21.6% (vs July 7, 2026). Sports was the largest domain by open interest (35%), ahead of Politics & Elections (27%); together they accounted for 62% of all open interest. Kalshi carried 78% of active markets and Polymarket 22%.
Deterministic · template v1 · 2026-07-08
As of 2026-07-08 · 00:00 UTC
Active Markets
157,476
00:00 UTC freeze
Open Interest
$1.61B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
20,393
with trading activity
Kalshi / Polymarket
78% / 22%
by active-market count
Domain Composition — 12 domains
Sports
101,683
Other
22,467
Mixed / Multi-category
17,735
Politics & Elections
6,457
Entertainment & Culture
2,462
Crypto & Digital Assets
2,160
Climate & Weather
1,114
Companies & Business
1,034
Economics & Inflation
885
Technology & AI
513
Monetary Policy
432
World & Geopolitics
421
Science & Health
113
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 = 157,476.
Largest Kalshi Series
Sports — multi-game parlays
77,657
Cross-category multi-markets
17,735
Midterm control
821
Music — artist streams
790
U.S. House races
588
Nextteamnba
418
Pgatour
390
NFL — next team moves
254
Mlbhr
252
California primaries
245
Nextteammlb
217
Nflwins
197
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 8, 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 8, 2026.” https://volroc.ai/prediction-markets/2026-07-08/
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