On June 20, 2026, VolRoc recorded 189,945 active prediction markets across Kalshi and Polymarket, holding $2.34B in combined open interest. Day over day, active markets rose 32.6% and open interest rose 9.0% (vs June 19, 2026). Sports was the largest domain by open interest (57%), ahead of Politics & Elections (16%); together they accounted for 73% of all open interest. Kalshi carried 99% of active markets and Polymarket 1%.
Deterministic · template v1 · 2026-06-20
As of 2026-06-20 · 00:00 UTC
Active Markets
189,945
00:00 UTC freeze
Open Interest
$2.34B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
29,403
with trading activity
Kalshi / Polymarket
99% / 1%
by active-market count
Domain Composition — 12 domains
Sports
141,888
Mixed / Multi-category
29,183
Other
11,006
Politics & Elections
3,761
Entertainment & Culture
2,145
Economics & Inflation
566
Crypto & Digital Assets
479
Companies & Business
304
Monetary Policy
271
Technology & AI
149
Climate & Weather
95
World & Geopolitics
67
Science & Health
31
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 = 189,945.
Largest Kalshi Series
Sports — multi-game parlays
130,953
Cross-category multi-markets
29,183
Music — artist streams
819
Midterm control
753
U.S. House races
606
Wcstageofelim
286
Nextteamnba
272
NFL — next team moves
253
Wctotal
245
California primaries
238
Mlbhr
231
Primarymov
209
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 June 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 — June 20, 2026.” https://volroc.ai/prediction-markets/2026-06-20/
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