On July 4, 2026, VolRoc recorded 282,401 active prediction markets across Kalshi and Polymarket, holding $2.47B in combined open interest. Day over day, active markets rose 25.0% and open interest rose 4.9% (vs July 3, 2026). Sports was the largest domain by open interest (55%), ahead of Politics & Elections (15%); together they accounted for 70% of all open interest. Kalshi carried 99% of active markets and Polymarket 1%.
Deterministic · template v1 · 2026-07-04
As of 2026-07-04 · 00:00 UTC
Active Markets
282,401
00:00 UTC freeze
Open Interest
$2.47B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
12,416
with trading activity
Kalshi / Polymarket
99% / 1%
by active-market count
Domain Composition — 12 domains
Sports
219,887
Mixed / Multi-category
43,073
Other
11,537
Politics & Elections
3,633
Entertainment & Culture
2,242
Economics & Inflation
580
Crypto & Digital Assets
527
Companies & Business
373
Monetary Policy
283
Climate & Weather
101
Technology & AI
80
World & Geopolitics
55
Science & Health
30
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 = 282,401.
Largest Kalshi Series
Sports — multi-game parlays
210,655
Cross-category multi-markets
43,073
Midterm control
802
Music — artist streams
794
U.S. House races
588
Nextteamnba
471
NFL — next team moves
254
Pgatour
248
California primaries
241
Nextteammlb
210
Primarymov
203
Nflwins
191
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 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 — July 4, 2026.” https://volroc.ai/prediction-markets/2026-07-04/
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