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Record October trading masks a different picture in outstanding political positions

The October 2026 report, built on Artemis data across 11 platforms, says politics and elections took under 5 percent of trading volume over the past year yet held 41.2 percent of open interest, while Kalshi and Polymarket together ran 97.7 percent of event contract volume.

Prediction-market trading volume reached a record 121.28 billion dollars in October 2026, rising 58.7 percent, according to VIP Grinders. Open interest increased 41.5 percent to 3.13 billion dollars.

The October 2026 report draws on Artemis data covering 11 platforms. Its figures show trading volume growing faster than open interest, alongside a pronounced difference between politics’ share of trading and its share of outstanding positions.

Politics carries more weight in open interest

Politics and elections accounted for under 5 percent of trading volume over the past year, according to VIP Grinders. Yet those categories represented 41.2 percent of open interest.

That contrast matters when interpreting market activity: the categories generating the most turnover are not necessarily those accounting for the largest share of positions still open. The political figures illustrate why volume alone offers an incomplete view.

Event contracts remain concentrated

Kalshi and Polymarket together accounted for 97.7 percent of event contract volume, according to VIP Grinders. That combined share indicates substantial concentration despite the report’s coverage of 11 platforms.

The findings, published Nov 4, 2026 at 2:00 PM ET, therefore present three distinct measures of the market: record overall trading, a large political share of open interest and event contract activity dominated by two platforms.

What it means for prediction markets

  • Turnover and outstanding exposure tell different stories. Politics and elections had under 5 percent of annual trading volume but 41.2 percent of open interest.
  • Growth was uneven across measures. Volume rose 58.7 percent, outpacing the 41.5 percent increase in open interest.
  • Platform concentration is central to interpreting activity. Kalshi and Polymarket’s combined 97.7 percent share applies specifically to event contract volume.
KalshiPolymarketInfiniti MarketsInfiniti Signals

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    VIP Grinders
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