On June 29, 2026, VolRoc recorded 100,414 active prediction markets across Kalshi and Polymarket, holding $2.06B in combined open interest. Day over day, active markets fell 54.3% and open interest fell 12.8% (vs June 28, 2026). Sports was the largest domain by open interest (45%), ahead of Politics & Elections (18%); together they accounted for 64% of all open interest. Kalshi carried 98% of active markets and Polymarket 2%.
Deterministic · template v1 · 2026-06-29
As of 2026-06-29 · 00:00 UTC
Active Markets
100,414
00:00 UTC freeze
Open Interest
$2.06B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
10,921
with trading activity
Kalshi / Polymarket
98% / 2%
by active-market count
Domain Composition — 12 domains
Sports
66,900
Mixed / Multi-category
13,814
Other
11,474
Politics & Elections
3,721
Entertainment & Culture
2,248
Crypto & Digital Assets
672
Economics & Inflation
624
Companies & Business
331
Monetary Policy
281
Technology & AI
145
Climate & Weather
106
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 = 100,414.
Largest Kalshi Series
Sports — multi-game parlays
58,726
Cross-category multi-markets
13,814
Music — artist streams
804
Midterm control
783
U.S. House races
606
Nextteamnba
371
Wcplayergoals
311
NFL — next team moves
254
California primaries
239
Primarymov
219
Wcstageofelim
205
Nextteammlb
203
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 29, 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 29, 2026.” https://volroc.ai/prediction-markets/2026-06-29/
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