On June 25, 2026, VolRoc recorded 211,452 active prediction markets across Kalshi and Polymarket, holding $2.28B in combined open interest. Day over day, active markets fell 26.4% and open interest fell 5.7% (vs June 24, 2026). Sports was the largest domain by open interest (52%), ahead of Politics & Elections (16%); together they accounted for 68% of all open interest. Kalshi carried 99% of active markets and Polymarket 1%.
Deterministic · template v1 · 2026-06-25
As of 2026-06-25 · 00:00 UTC
Active Markets
211,452
00:00 UTC freeze
Open Interest
$2.28B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
13,880
with trading activity
Kalshi / Polymarket
99% / 1%
by active-market count
Domain Composition — 12 domains
Sports
159,819
Mixed / Multi-category
32,285
Other
11,273
Politics & Elections
3,764
Entertainment & Culture
2,217
Crypto & Digital Assets
601
Economics & Inflation
588
Companies & Business
302
Monetary Policy
280
Technology & AI
142
Climate & Weather
83
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 = 211,452.
Largest Kalshi Series
Sports — multi-game parlays
149,669
Cross-category multi-markets
32,285
Music — artist streams
817
Midterm control
762
U.S. House races
606
Nextteamnba
324
Wcstageofelim
269
NFL — next team moves
253
California primaries
239
Primarymov
231
Primary vote shares
222
Wcteamleadgoal
211
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 25, 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 25, 2026.” https://volroc.ai/prediction-markets/2026-06-25/
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