On June 17, 2026, VolRoc recorded 146,477 active prediction markets across Kalshi and Polymarket, holding $2.09B in combined open interest. Day over day, active markets rose 43.1% and open interest rose 8.5% (vs June 16, 2026). Sports was the largest domain by open interest (50%), ahead of Politics & Elections (19%); together they accounted for 68% of all open interest. Kalshi carried 94% of active markets and Polymarket 6%.
Deterministic · template v1 · 2026-06-17
As of 2026-06-17 · 00:00 UTC
Active Markets
146,477
00:00 UTC freeze
Open Interest
$2.09B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
16,266
with trading activity
Kalshi / Polymarket
94% / 6%
by active-market count
Domain Composition — 12 domains
Sports
101,550
Mixed / Multi-category
21,695
Other
12,358
Politics & Elections
5,518
Entertainment & Culture
2,187
Crypto & Digital Assets
1,038
Economics & Inflation
701
Companies & Business
428
Monetary Policy
386
Technology & AI
301
World & Geopolitics
160
Climate & Weather
85
Science & Health
70
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 = 146,477.
Largest Kalshi Series
Sports — multi-game parlays
88,806
Cross-category multi-markets
21,695
Music — artist streams
852
Midterm control
735
U.S. House races
604
Wctotal
292
Wcstageofelim
279
Mlbhr
272
Nextteamnba
260
NFL — next team moves
253
Wcteamtotal
236
California primaries
233
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 17, 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 17, 2026.” https://volroc.ai/prediction-markets/2026-06-17/
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