Kalshi Holds 76% of Tracked Volume as Polymarket US Grows 66%

Kalshi accounted for 75.7% of face-value contract volume across nine tracked prediction-market venues over the 30 UTC days from Sept. 29 through Oct. 28, giving it the largest share of the latest measured period. Polymarket US represented 11.6%, while Polymarket International accounted for 4.1%. Together, Polymarket’s venues made up 15.7% of tracked volume. The venues recorded $120.3 billion in face-value contracts, while traders paid $29 billion. Kalshi logged $90.9 billion in volume and $20.6 billion paid. Polymarket US recorded $13.9 billion in volume and $3.3 billion paid; Polymarket International recorded $4.9 billion and $2.5 billion, respectively.