Among the three, Kalshi saw the largest month-over-month increase in volume, growing 87.4% to $31.5 billion from $16.81 billion.

Kalshi and Polymarket processed nearly $45B in June trades, a 75% monthly jump driven by sports betting. Here's what the surge means for investors.

Among the three, Kalshi saw the largest month-over-month increase in volume, growing 87.4% to $31.5 billion from $16.81 billion.