Overview
- The combined weekly notional volume on Kalshi and Polymarket reached $2.7 billion in mid‑October, driven mostly by very short Bitcoin price contracts.
- Kalshi reported that its 15‑minute up/down Bitcoin contracts accounted for more than $2 billion of that total while Polymarket’s U.S. arm logged about $92 million to $101 million in 15‑minute BTC volume in its first full week.
- The $2.7 billion figure measures notional volume, meaning the face value of contracts traded rather than user deposits, capital at risk, or platform revenue, so high turnover can overstate actual economic exposure.
- State regulators are already intervening on some contract types, with Michigan limiting sports markets in Coinbase’s Kalshi‑operated offering, a development that could narrow where certain event contracts are available.
- The surge reflects exchanges’ push for new engagement as spot trading slows and leaves open questions about how long the pace will last, who the active traders are, and how regulators and platforms will shape product rollout.