On July 27, 2026, VolRoc recorded 93,953 active prediction markets across Kalshi and Polymarket, holding $1.16B in combined open interest. Day over day, active markets fell 49.8% and open interest fell 28.0% (vs July 26, 2026). Politics & Elections was the largest domain by open interest (41%), ahead of Sports (25%); together they accounted for 66% of all open interest. Kalshi carried 59% of active markets and Polymarket 41%.
Deterministic · template v1 · 2026-07-27
As of 2026-07-27 · 00:00 UTC
Active Markets
93,953
00:00 UTC freeze
Open Interest
$1.16B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
16,002
with trading activity
Kalshi / Polymarket
59% / 41%
by active-market count
Domain Composition — 12 domains
Sports
47,282
Other
25,482
Politics & Elections
6,701
Mixed / Multi-category
4,887
Entertainment & Culture
2,703
Crypto & Digital Assets
1,720
Companies & Business
1,457
Technology & AI
1,196
Economics & Inflation
937
Climate & Weather
586
Monetary Policy
460
World & Geopolitics
457
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 = 93,953.
Largest Kalshi Series
Sports — multi-game parlays
24,985
Cross-category multi-markets
4,887
Midterm control
906
Music — artist streams
767
U.S. House races
599
Nextteamnba
462
NFL — next team moves
255
Nflwins
244
Nextteammlb
231
Flprimary
195
Rt
164
Mlbseasonhr
161
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 27, 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 27, 2026.” https://volroc.ai/prediction-markets/2026-07-27/
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