ACDC finds most midterm prediction markets movable for $3,500 or less

The Anti-Corruption Data Collective (ACDC) found that 96% of congressional prediction markets with live order books could be shifted five cents for $3,500 or less, even as $431 million has already been wagered on those markets. The findings, published November 2, cover 28,845 congressional markets across Kalshi, Polymarket and Polymarket US, with betting volumes nearly tripling compared with the 2024 congressional elections. There are also 61 times as many markets as in the last congressional election cycle.

In an interview with Gambling Insider, ACDC Research Fellow Michelle Kendler-Kretsch said researchers had been surprised how cheap it was to move many of these markets. ACDC’s latest figures show that 66% of live congressional markets could be moved five cents for less than $100, while only 244 required more than $10,000. Even among the most expensive markets within each of the 470 congressional races, 90% could be shifted five cents for less than $25,000.

Transparency measures

Kalshi rolled out new transparency tools in October, including low-volume warnings. ACDC found that 90% of congressional markets across the three platforms had trading volumes below $10,000. Kendler-Kretsch said the tools still do not solve transparency issues for independent auditing of vulnerabilities and risks, while Polymarket lets researchers see the user behind every trade. Gambling Insider contacted Kalshi for comment on ACDC’s findings and criticism of its transparency measures but had not received a response at the time of publication.

ACDC’s analysis found that the top 1% of Polymarket wallets now account for 75% of congressional trading volume, up from 68% in August, despite 89,453 unique wallets participating across 7,397 markets. A typical congressional market had just 48 bettors. Matt Cepulis, founder and CEO of 3betmedia, told Gambling Insider: “The trade is cheap; the screenshot is the product.”

Response

Paul Krishnamurty, chief political oddsmaker for BetOnline.ag, disputes the suggestion that inexpensive price movements pose a significant electoral threat. He said he has never heard any evidence that betting odds or narrative shifts voters, and that market moves of a few cents are irrelevant because 5c doesn’t reflect a meaningful shift in odds. Krishnamurty said BetOnline was taking between $30,000 and $50,000 in daily bets on Senate races.