On July 9, 2026, VolRoc recorded 217,704 active prediction markets across Kalshi and Polymarket, holding $1.86B in combined open interest. Day over day, active markets rose 38.2% and open interest rose 15.7% (vs July 8, 2026). Sports was the largest domain by open interest (41%), ahead of Politics & Elections (24%); together they accounted for 65% of all open interest. Kalshi carried 84% of active markets and Polymarket 16%.
Deterministic · template v1 · 2026-07-09
As of 2026-07-09 · 00:00 UTC
Active Markets
217,704
00:00 UTC freeze
Open Interest
$1.86B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
21,244
with trading activity
Kalshi / Polymarket
84% / 16%
by active-market count
Domain Composition — 12 domains
Sports
152,150
Mixed / Multi-category
26,376
Other
23,361
Politics & Elections
6,532
Entertainment & Culture
2,572
Crypto & Digital Assets
2,103
Climate & Weather
1,163
Companies & Business
1,039
Economics & Inflation
909
Technology & AI
513
Monetary Policy
446
World & Geopolitics
427
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 = 217,704.
Largest Kalshi Series
Sports — multi-game parlays
128,608
Cross-category multi-markets
26,376
Midterm control
828
Music — artist streams
791
U.S. House races
589
Pgatour
429
Nextteamnba
422
NFL — next team moves
254
Mlbhr
250
California primaries
245
Nextteammlb
217
Mlbhit
202
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 9, 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 9, 2026.” https://volroc.ai/prediction-markets/2026-07-09/
Get the daily statistics
A short daily read on the prediction-market universe across Kalshi and Polymarket.
Join the list →