On August 9, 2026, VolRoc recorded 177,523 active prediction markets across Kalshi and Polymarket, holding $1.44B in combined open interest. Day over day, active markets fell 12.6% and open interest fell 4.4% (vs August 8, 2026). Sports was the largest domain by open interest (38%), ahead of Politics & Elections (35%); together they accounted for 72% of all open interest. Kalshi carried 92% of active markets and Polymarket 8%.
Deterministic · template v1 · 2026-08-09
As of 2026-08-09 · 00:00 UTC
Active Markets
177,523
00:00 UTC freeze
Open Interest
$1.44B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
16,169
with trading activity
Kalshi / Polymarket
92% / 8%
by active-market count
Domain Composition — 12 domains
Sports
112,766
Mixed / Multi-category
33,272
Other
17,445
Politics & Elections
6,275
Entertainment & Culture
2,696
Crypto & Digital Assets
1,376
Economics & Inflation
1,000
Technology & AI
911
Companies & Business
743
Monetary Policy
403
World & Geopolitics
372
Climate & Weather
188
Science & Health
76
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 = 177,523.
Largest Kalshi Series
Sports — multi-game parlays
100,772
Cross-category multi-markets
33,272
Midterm control
1,017
Music — artist streams
742
U.S. House races
607
Nextteamnba
496
Mlbhr
300
Nflwins
292
Mlbhrr
251
Mlbhit
233
NFL — next team moves
228
Rt
220
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 August 9, 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 — August 9, 2026.” https://volroc.ai/prediction-markets/2026-08-09/
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