Polymarket's share of the prediction market has fallen from 96% to 27% over two years, according to a post on X. Kalshi, a CFTC-regulated exchange, logged roughly $65 billion in October volume and now leads the sector.
According to a widely shared post on X, Polymarket's market share fell from 96% to 27% over two years. The same post says Kalshi now trades nearly three times Polymarket's volume.
Kalshi logs $65 billion in October volume against $10 billion for Polymarket US
Kalshi logged roughly $65 billion in trading volume in October 2026, about 10% higher than September. Polymarket US, the platform's American arm, recorded $10 billion in October volume, a gain of about 15% month over month.
Among US-regulated platforms combined, Kalshi held around 83% of market share in October 2026. Polymarket US sat at roughly 12% to 15% in recent snapshots, while Polymarket Global is down in the single digits.
Open interest shows a similar gap. Kalshi carried about $2.05 billion in October, against about $384 million for Polymarket US.
Regulation and brokerage distribution drive Kalshi's rise
Polymarket built its reputation during the 2024 US election cycle with an on-chain model, where trades settle on a blockchain using crypto. Kalshi took a different route as an exchange regulated by the CFTC, the federal agency that oversees futures markets.
The source names three factors in Kalshi's rise. The first is regulatory clarity. The second is distribution, with partnerships with Robinhood and Coinbase putting Kalshi contracts in front of existing brokerage accounts. The third is product breadth, as Kalshi expanded into sports and combo or parlay-style bets.
Polymarket US grows faster, but the volume gap widens
Polymarket US posted faster monthly growth than Kalshi in October, around 15% versus around 10%. However, percentage growth on a $10 billion base and a $65 billion base produces very different dollar gains, so the gap in raw volume is still widening for now.
October 2026 also brought record-high open interest across the sector heading into the US midterm elections. Kalshi appears positioned to capture the bulk of that cycle.
Source: Crypto Briefing
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