TLDR Americans have wagered $431 million on congressional prediction markets ahead of Tuesday’s midterms. 96% of live congressional markets could be shifted five cents for $3,500 or less. The top 1% of Polymarket wallets drive 75% of congressional trading volume. Researchers flagged 591 suspicious round-trip trades worth $618,395 that produced just $34 in profit. Kalshi has not responded to criticism that its new transparency tools still hide key trading data.
Americans head to the polls on Tuesday for the 2026 midterm elections, and $431 million has already been wagered on congressional prediction markets. New research shows the odds in most of those markets can still be moved for less than $3,500.
The Anti-Corruption Data Collective (ACDC) published the findings on November 2. The report covers 28,845 congressional markets across Kalshi, Polymarket, and Polymarket US.
Betting volume has nearly tripled compared with the 2024 congressional elections. There are also 61 times as many markets as in the last cycle, but the money is not spread evenly between them.
Most Markets Remain Cheap to Move
ACDC found that 96% of congressional markets with live order books could be shifted five cents for $3,500 or less. About 66% could be moved five cents for under $100, while only 244 needed more than $10,000.
The group also looked at the hardest market to move in each of the 470 congressional races. Even among those, 90% could be shifted five cents for less than $25,000.
“We were actually surprised when we did our initial research in September how cheap it was to move many of these markets,” ACDC Research Fellow Michelle Kendler-Kretsch told Gambling Insider. The figures show the cost of moving a price, not proof that anyone tried to rig a race.
Kalshi added low-volume warnings and forecasting accuracy measures in