On October 5, 2026, VolRoc recorded 248,405 active prediction markets across Kalshi and Polymarket, holding $732.9M in combined open interest. Day over day, active markets fell 34.7% and open interest fell 41.0% (vs October 4, 2026). Politics & Elections was the largest domain by open interest (37%), ahead of Sports (12%); together they accounted for 49% of all open interest. Kalshi carried 89% of active markets and Polymarket 11%.
Deterministic · template v1 · 2026-10-05
As of 2026-10-05 · 00:00 UTC
Active Markets
248,405
00:00 UTC freeze
Open Interest
$732.9M
Kalshi OI + Polymarket liquidity
Markets Traded · 24h
8,126
with trading activity
Kalshi / Polymarket
89% / 11%
by active-market count
Domain Composition — 12 domains
Mixed / Multi-category
220,012
Sports
11,070
Other
8,214
Politics & Elections
5,361
Crypto & Digital Assets
1,144
Technology & AI
755
World & Geopolitics
666
Entertainment & Culture
343
Companies & Business
310
Economics & Inflation
226
Monetary Policy
129
Climate & Weather
127
Science & Health
48
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 = 248,405.
Largest Kalshi Series
Cross-category multi-markets
186,439
KXMVECROSSCATEGORY0
33,573
Btcd
99
Ncaafspread
87
Mlbhrr
74
Mlbhit
71
Nhlgoal
65
Mlbtb
58
Ncaaftotal
57
Mlbhr
57
Atpmatch
52
Mlbks
39
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 October 5, 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 — October 5, 2026.” https://volroc.ai/prediction-markets/2026-10-05/
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