Weekly prediction-market volume tops $20bn for first time ever

Nadex, Rothera, Predict.fun & Opinion trailed far behind, with the top two combining for over $19bn.

The hit

Prediction markets posted $20.4bn in cumulative weekly trading volume, the first time weekly volume has crossed $20bn, according to Artemis data. Kalshi took around $15.8bn of that, roughly 77%, with Polymarket a distant second on $3.6bn. The total beat the previous peak set during the FIFA World Cup in June & July 2026.

Why it matters

The record reflects three catalysts stacking at once: NFL & college football combo contracts, short-duration crypto price bets & early positioning on the November 3 midterms. Kalshi counts parlay contracts at their $1 payout value rather than the price paid, so headline volume runs well ahead of actual capital at risk, according to Cryptopolitan’s analysis.

The record

Weekly volume record	$20.4bn, up from $19.8bn the prior week (Artemis)
Kalshi’s share	$15.8bn, about 77% of total volume (Artemis)
Polymarket’s share	$3.6bn, second place (Artemis)
Smaller venues	Nadex $481.9m, Rothera $272.3m, Predict.fun & Opinion each over $120m (Artemis)
Court ruling	6th Circuit ruled Ohio & Tennessee can regulate Kalshi’s sports contracts, 25 September

What happens next

Watch weekly volume through the NFL season, which runs into early January 2027, & into the November 3 midterm elections, where control of Congress is at stake.

Sources: Prediction Markets Log $20.4B Week as Kalshi Takes 77%

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