Matched market index highlights contrasting scale at Polymarket and Kalshi
The comparison index counts 2,941 open questions on Polymarket carrying 6.3 billion dollars in volume on open markets, against 6,463 open questions on Kalshi with 2.2 billion dollars. Prices on the page come from the Polymarket global book, while Kalshi figures cover its CFTC-regulated US exchange.
Predictions.io tracked 1,597 validated matches between Polymarket and Kalshi questions as of October 31, 2026, according to its comparison index. The snapshot was published at 2:30 PM ET.
Open questions and volume
The index counted 2,941 open questions on Polymarket, with $6.3 billion in volume on open markets. Kalshi had 6,463 open questions and $2.2 billion in volume on open markets, according to Predictions.io.
The figures show different measures of scale: Kalshi had more open questions, while Polymarket recorded greater volume across its open markets. The 1,597 validated matches provide a narrower set for comparing questions across the two venues.
Scope of the comparison
The data also carry an important venue distinction. Prices displayed on the page come from Polymarket’s global book, while the Kalshi figures cover its CFTC-regulated US exchange.
What it means for prediction markets
- Matched questions are a distinct subset. The 1,597 validated matches should not be confused with either platform’s total number of open questions.
- Breadth and volume tell different stories. Kalshi leads this snapshot in open-question count; Polymarket leads in volume on open markets.
- Venue scope matters. Readers comparing the figures should retain the distinction between Polymarket’s global book and Kalshi’s CFTC-regulated US exchange.
Sources & attribution
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