Kalshi and Polymarket US Top Monthly Volume Records Before Month-End

Kalshi and Polymarket US had surpassed their previous monthly trading-volume records in October month-to-date figures before the Nov. 3 midterms, though the totals do not isolate election activity. Kalshi’s October month-to-date volume was about $65 billion, roughly 10% above its September record. Polymarket US reached about $10 billion, about 15% above its September total, extending its run after a September contract-volume record . The figures measure notional volume, which counts contracts at face value rather than the cash traders paid. They track trading activity, but do not represent traders’ cash outlay.