On June 30, 2026, VolRoc recorded 193,216 active prediction markets across Kalshi and Polymarket, holding $2.26B in combined open interest. Day over day, active markets rose 92.4% and open interest rose 9.9% (vs June 29, 2026). Sports was the largest domain by open interest (50%), ahead of Politics & Elections (17%); together they accounted for 66% of all open interest. Kalshi carried 99% of active markets and Polymarket 1%.
Deterministic · template v1 · 2026-06-30
As of 2026-06-30 · 00:00 UTC
Active Markets
193,216
00:00 UTC freeze
Open Interest
$2.26B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
11,942
with trading activity
Kalshi / Polymarket
99% / 1%
by active-market count
Domain Composition — 12 domains
Sports
147,047
Mixed / Multi-category
26,789
Other
11,342
Politics & Elections
3,688
Entertainment & Culture
2,227
Crypto & Digital Assets
635
Economics & Inflation
615
Companies & Business
301
Monetary Policy
283
Climate & Weather
112
Technology & AI
87
World & Geopolitics
59
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 = 193,216.
Largest Kalshi Series
Sports — multi-game parlays
138,074
Cross-category multi-markets
26,789
Music — artist streams
801
Midterm control
788
U.S. House races
607
Nextteamnba
391
NFL — next team moves
254
California primaries
240
Primarymov
218
Pgatour
216
Mlbhr
211
Nextteammlb
207
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 30, 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 30, 2026.” https://volroc.ai/prediction-markets/2026-06-30/
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