On July 20, 2026, VolRoc recorded 99,158 active prediction markets across Kalshi and Polymarket, holding $1.20B in combined open interest. Day over day, active markets fell 59.3% and open interest fell 39.5% (vs July 19, 2026). Politics & Elections was the largest domain by open interest (37%), ahead of Sports (32%); together they accounted for 69% of all open interest. Kalshi carried 59% of active markets and Polymarket 41%.
Deterministic · template v1 · 2026-07-20
As of 2026-07-20 · 00:00 UTC
Active Markets
99,158
00:00 UTC freeze
Open Interest
$1.20B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
16,897
with trading activity
Kalshi / Polymarket
59% / 41%
by active-market count
Domain Composition — 12 domains
Sports
49,867
Other
27,042
Politics & Elections
6,442
Mixed / Multi-category
6,166
Entertainment & Culture
2,586
Crypto & Digital Assets
2,178
Climate & Weather
1,185
Companies & Business
1,153
Economics & Inflation
876
Technology & AI
649
World & Geopolitics
487
Monetary Policy
442
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 = 99,158.
Largest Kalshi Series
Sports — multi-game parlays
27,247
Cross-category multi-markets
6,166
Midterm control
870
Music — artist streams
778
U.S. House races
593
Nextteamnba
443
NFL — next team moves
254
Nextteammlb
221
Nflwins
212
Flprimary
191
Mlbseasonhr
161
Albumequiv
149
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 20, 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 20, 2026.” https://volroc.ai/prediction-markets/2026-07-20/
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