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Bettors have reportedly wagered over $220 million on the outcomes of the November midterms on prediction markets Kalshi and Polymarket.
That’s more than twice the $92 million in trading volume recorded during the entire 2024 congressional election cycle, Reuters reported Thursday, citing data from the Anti-Corruption Data Collective.
The analysis covered more than 21,000 congressional election markets this cycle, compared with just 463 involving congressional races two years ago.
Despite the explosion of bets most of the trading volume is concentrated in a few races — particularly the Texas Senate contest between Republican Ken Paxton and Democrat James Talarico.
Senate races in Maine, Michigan and South Carolina have also attracted heavy betting, according to the research.
A small cluster of accounts has dominated midterm election betting on Polymarket’s international platform, where the top 1% of wallets accounted for 70% of congressional trading volume this cycle.
Bettors are increasingly wagering on more than which candidate will emerge victorious.
Some 58% of this year’s congressional betting markets focus on victory margins, while just 16% involve picking winners — down from 71% in 2024.
However, many of the narrowly focused markets have attracted little trading, according to ACDC researcher Michelle Kendler-Kretsch.
Bets on outright winners still account for the vast majority of trading volume.
The expansion of election betting has also raised concerns among policymakers and advocacy groups about potential insider trading and the risks that wagering could pose to public confidence in elections.
NPR reported in May that unspecified campaign staffers had placed bets on races they worked on. And Kalshi has suspended a handful of candidates for wagering on their own contests, according to Reuters.
The platform bars politicians and campaign workers from betting on elections — and banned disgraced ex-Rep. George Santos for life after he was caught betting on whether he’d attend the State of the Union address earlier this year.
Polymarket, meanwhile, has defended its ability to police potential misconduct.
“We use state-of-the-art surveillance and dedicated detection systems built for political markets,” a Polymarket spokesperson told Reuters.
The company also claims its election markets are 98% accurate one day before voting.
“Election prediction markets focus a disruptive new financial technology on our democratic process,” Michelle Kendler-Kretsch, a researcher at the Anti-Corruption Data Collective, told Reuters.
A Reuters/Ipsos poll published Monday found that most Americans oppose betting on elections through prediction markets.
The Post has sought comment from Kalshi and Polymarket.