On July 19, 2026, VolRoc recorded 243,358 active prediction markets across Kalshi and Polymarket, holding $1.99B in combined open interest. Day over day, active markets rose 12.9% and open interest rose 4.2% (vs July 18, 2026). Sports was the largest domain by open interest (49%), ahead of Politics & Elections (23%); together they accounted for 72% of all open interest. Kalshi carried 85% of active markets and Polymarket 15%.
Deterministic · template v1 · 2026-07-19
As of 2026-07-19 · 00:00 UTC
Active Markets
243,358
00:00 UTC freeze
Open Interest
$1.99B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
19,650
with trading activity
Kalshi / Polymarket
85% / 15%
by active-market count
Domain Composition — 12 domains
Sports
173,544
Mixed / Multi-category
27,496
Other
26,460
Politics & Elections
6,458
Entertainment & Culture
2,632
Crypto & Digital Assets
1,959
Climate & Weather
1,197
Companies & Business
1,090
Economics & Inflation
857
Technology & AI
652
World & Geopolitics
489
Monetary Policy
439
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 = 243,358.
Largest Kalshi Series
Sports — multi-game parlays
150,973
Cross-category multi-markets
27,496
Midterm control
868
Music — artist streams
775
U.S. House races
593
Nextteamnba
442
NFL — next team moves
254
Nextteammlb
221
Nflwins
210
Wcaward
206
Flprimary
191
Albumequiv
177
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 19, 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 19, 2026.” https://volroc.ai/prediction-markets/2026-07-19/
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