On August 16, 2026, VolRoc recorded 204,171 active prediction markets across Kalshi and Polymarket, holding $1.57B in combined open interest. Day over day, active markets rose 8.1% and open interest rose 3.6% (vs August 15, 2026). Sports was the largest domain by open interest (34%), ahead of Politics & Elections (33%); together they accounted for 67% of all open interest. Kalshi carried 94% of active markets and Polymarket 6%.
Deterministic · template v1 · 2026-08-16
As of 2026-08-16 · 00:00 UTC
Active Markets
204,171
00:00 UTC freeze
Open Interest
$1.57B
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
16,292
with trading activity
Kalshi / Polymarket
94% / 6%
by active-market count
Domain Composition — 12 domains
Mixed / Multi-category
90,863
Sports
81,702
Other
17,915
Politics & Elections
6,247
Entertainment & Culture
2,681
Crypto & Digital Assets
1,332
Technology & AI
893
Economics & Inflation
843
Companies & Business
715
Monetary Policy
410
World & Geopolitics
310
Climate & Weather
184
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 = 204,171.
Largest Kalshi Series
Cross-category multi-markets
90,863
Sports — multi-game parlays
69,089
Midterm control
1,077
Music — artist streams
735
U.S. House races
612
Nextteamnba
507
Nflwins
325
Ncaafwins
248
Mlbhr
246
Mlbhit
240
NFL — next team moves
230
Primary vote shares
225
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 16, 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 16, 2026.” https://volroc.ai/prediction-markets/2026-08-16/
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