US midterms: Prediction markets favor Democrats in key crypto races

Kalshi and Polymarket price a 75% chance of a Democratic sweep, days after markets misjudged Brazil’s runoff.

As Americans across the country head to the polls for the US midterm elections Tuesday, prediction market traders have spent months wagering on the outcome. According to an analysis by The Washington Post, nearly $1.9 billion in election-related contracts had traded on Kalshi and Polymarket as of Monday, marking record trading activity for a midterm election cycle.

Markets on both platforms favor Democrats winning control of Congress, with a Democratic sweep priced at 75% on Kalshi and 75.5% on Polymarket as of 4:30 p.m. UTC. Kalshi traders gave Democrats a 93% chance of taking the House and a 75% chance of winning the Senate, while Polymarket priced those outcomes at 94.5% and 75.5%, respectively.

The vote comes nine days after prediction markets failed to anticipate the outcome of Brazil’s presidential election, with Flávio Bolsonaro favored at roughly 80% the day before incumbent President Luiz Inácio Lula da Silva won the runoff. Kalshi CEO Tarek Mansour reportedly cautioned that “a 5% probability doesn’t mean it won’t happen,” according to CNBC.

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