Election Odds Can Still Be Moved for $3,500 as Midterm Betting Hits $431 Million

Exclusive: With $431 million wagered on congressional races, ACDC researcher Michelle Kendler-Kretsch questions whether Kalshi’s transparency measures tell voters enough about the money behind election odds.

With Americans heading to the polls on Tuesday, $431 million has already been wagered on congressional prediction markets. For all that money, the odds in most of those markets can still be shifted for less than $3,500.

The Anti-Corruption Data Collective (ACDC) found that 96% of congressional markets with live order books could be shifted five cents for $3,500 or less, even as trading activity increased ahead of the midterms. In an exclusive interview with Gambling Insider, ACDC Research Fellow Michelle Kendler-Kretsch said the concern is what happens when those prices are passed around as evidence that a candidate is winning.

“We were actually surprised when we did our initial research in September how cheap it was to move many of these markets.” – Michelle Kendler-Kretsch, Anti-Corruption Data Collective Research Fellow

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, although the money is far from evenly spread between them.

Even the Biggest Markets in Most Races Can Be Moved for Under $25,000

When ACDC first looked at congressional prediction markets in September, researchers expected prices to become harder to move as Election Day approached. That has happened in some races, but thousands of contracts remain cheap to shift.

“We were actually surprised when we did our initial research in September how cheap it was to move many of these markets,” she told Gambling Insider. “They don’t have enough sufficient volume for another trader to counter them very quickly.”

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.

ACDC deliberately looked at the hardest market to move in each race, rather than relying solely on obscure contracts that barely attract a bet. Even those prices could often be shifted for less than the cost of a conventional campaign advertising push.

“Even two months later from that initial research, we still find that it’s very, very cheap to do because there’s so many markets, a lot of them don’t have large volumes,” Kendler-Kretsch said.

The calculations show what it would cost to move a price, not whether anybody has tried to rig an election. ACDC cannot tell from the trading records alone why someone placed a particular bet.

Kalshi’s Transparency Warnings Apply to Most Election Markets

Kalshi rolled out new transparency tools in October, including low-volume warnings and measures of forecasting accuracy. Kendler-Kretsch said the warnings were useful for people unfamiliar with prediction markets, but they also highlighted just how many contracts have little trading activity.

“If you have to label that many markets, should you offer that many markets in the first place?” she asked.

ACDC found that 90% of congressional markets across the three platforms had trading volumes below $10,000, six percentage points more than in September. That is the threshold Kalshi uses to flag markets where limited trading can make prices less reliable.

What Kendler-Kretsch wanted from Kalshi was access to the trading records behind those prices. She said the new tools still do not show researchers which accounts are placing large orders or how much influence individual traders have over a market.

“The data is still the same; it’s just being presented differently, which has positives for users who are unfamiliar, but doesn’t solve the transparency issues in terms of independent auditing of the vulnerabilities and risks.”

Polymarket, by comparison, allows researchers to follow transactions through publicly visible wallets. They cannot necessarily identify the person behind an account, but they can see whether it trades regularly, places unusually large bets, or operates across several markets.

“On Polymarket, I can see the user that did every trade. I can see every trade,” she explained. “All of those different activities and behaviors allow us to better analyze bets and suspicious bets. And that’s just simply not available on Kalshi.”

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.

One Percent of Polymarket Wallets Now Drive 75% of Congressional Trading

ACDC’s latest analysis found that the top 1% of Polymarket wallets now account for 75% of congressional trading volume, up from 68% in August. The concentration comes despite 89,453 unique wallets participating across 7,397 markets.

A typical congressional market had just 48 bettors, while only 32 markets attracted more than 1,000 unique participants. The report also found that 79% of trades involved either heavily funded accounts or algorithmic traders.

“A five-cent jump on a thin House market becomes a chart, the chart becomes a post saying ‘momentum is shifting,’ and that post reaches far more people than ever look at the order book.”

Matt Cepulis, founder and CEO of 3betmedia, said those conditions could be exploited by anyone looking to give a candidate some cheap publicity. He has spent more than nine years working in cryptocurrency marketing, where a small price movement can become a much bigger story once influencers get ahold of it.

“The trade is cheap; the screenshot is the product,” Cepulis told Gambling Insider.

“A five-cent jump on a thin House market becomes a chart, the chart becomes a post saying ‘momentum is shifting’, and that post reaches far more people than ever look at the order book.” – Matt Cepulis, 3betmedia CEO

Kendler-Kretsch made a related point about how journalists report election odds. A poll normally comes with a sample size, fieldwork dates, and an explanation of how the research was conducted, whereas a prediction market figure may appear in a headline with none of that information.

“All you have to do is take a screenshot of the elevated price,” she said. “It can last one second; it can last three hours.”

Even if other traders bring the price back down, the original image can keep circulating. Anyone seeing it later may have no idea that the odds changed again minutes after the screenshot was taken.

Political Oddsmaker Says Five-Cent Moves Are Too Small to Matter

Paul Krishnamurty, chief political oddsmaker for BetOnline.ag, disputes the suggestion that inexpensive price movements pose a significant electoral threat. He said five-cent fluctuations are commonplace and unlikely to attract much attention outside betting circles.

“I have never heard any evidence that betting odds or narrative shifts voters.” – Paul Krishnamurty, BetOnline.ag chief political oddsmaker

“I would say market moves of a few cents are irrelevant. Not newsworthy or dramatic. 5c doesn’t reflect a meaningful shift in odds,” he told Gambling Insider. “It happens all day, every day. It wouldn’t gain any media traction, which would be the aim of such a strategy.”

Krishnamurty said BetOnline was taking between $30,000 and $50,000 in daily bets on Senate races, with considerably more money changing hands on contests that attract national interest. He argued that anyone trying to move those headline prices would need much deeper pockets.

“Only markets which capture media attention are the major ones, which would require huge sums to manipulate, with very little prospect of success,” he said.

Ben Head, COO of UK-licensed bookmaker BetGoodwin, sees the $3,500 finding primarily as evidence of how little trading takes place in many congressional contracts. He also pointed to a difference between prediction exchanges and traditional bookmakers, where a trader can decide whether an unusual bet warrants changing the odds.

“The $3,500 figure isn’t really about manipulation. It shows how little money is in most of these markets,” Head said. “When a few hundred dollars is all that’s been traded on a House race, the price you see isn’t a crowd consensus. It’s just the last trade.”

Head said someone seeking to boost a candidate’s image might be happy to lose money on the trade if the resulting odds generated publicity. In that scenario, the bet is effectively an advertising expense rather than an attempt to predict the result.

Kimi Yu, founder of AskSpinner, drew a line between moving market prices and changing minds at the ballot box. He said there was much less evidence for the latter.

“Two separate questions. Can a few thousand dollars move a thin election contract? Yes, a price is only as deep as its order book. Does that move voters? The evidence is weaker.”

Spencer Pratt’s Betting Odds Fueled Claims After His Election Defeat

Kendler-Kretsch pointed to ACDC’s investigation with CNBC into Kalshi trading during the Los Angeles mayoral primary as an example of the risks surrounding election coverage. Researchers found that prices backing reality television personality Spencer Pratt repeatedly recovered after negative polling or news about his campaign.

Pratt ultimately failed to advance, but some online influencers subsequently questioned the election result, citing prediction market prices. Some had partnership deals with Kalshi at the time, according to ACDC, although the researchers could not establish whether the trading reflected genuine enthusiasm for Pratt or an attempt to keep his odds elevated.

Kendler-Kretsch said people can also misunderstand what a probability actually promises. If a candidate has an 80% chance of winning, losing is still one of the possible outcomes, and not proof that the election was stolen or the market was rigged.

The Brennan Center for Justice recently tested how prediction market prices affect voters’ expectations. Its survey, cited in ACDC’s latest report, found that respondents were between 10 and 20 percentage points more likely to believe a market-favored candidate would win, regardless of what the polls said.

That points out that betting odds could influence expectations, but it does not show that people vote differently because of them. Whether that happens is a question researchers have yet to answer.

More Than $618,000 Passed Through Suspicious Trades for $34 in Profit

ACDC also found unusual activity in congressional markets involving candidates with little chance of winning. Its researchers identified 591 suspicious round-trip transactions across 22 Polymarket markets, involving 544 separate wallets.

The pattern was straightforward: buy contracts priced at 95 cents or more, then sell almost everything back within six hours without making or losing much money. Across the transactions, $618,395 changed hands, but the combined profit amounted to just $34.

The average trade involved $1,046 and was completed in nine minutes, with almost half taking less than five minutes. ACDC said such transactions could be attractive to people seeking to inflate trading volumes or move money through the platform.

One example involved Robert Lebovics, an outsider candidate for the Republican Senate nomination in New Jersey. More than 100 suspicious transactions worth nearly a quarter of a million dollars passed through his market, despite his implied chance of winning being around 3%.

ACDC has not established that these trades involved wash trading or money laundering. Its concern is that contracts on near-certain outcomes offer a convenient way to move substantial sums without taking much financial risk.

Campaign Insiders Could Profit From Information Voters Have Yet to Hear

ACDC also identified $25.5 million wagered on congressional contracts involving outcomes that people connected to political campaigns could potentially know in advance. These include endorsements, candidate appearances, and other campaign activities that may be decided privately before being announced.

Kendler-Kretsch said another unresolved issue concerns whether trading intended to help a candidate could fall within campaign-finance rules. Foreign nationals cannot legally contribute to US political campaigns, but participation in election prediction markets raises different questions.

She said legal experts consulted by ACDC had suggested that trades directed by a campaign as part of its strategy could potentially qualify as in-kind contributions. Independent betting, however, would not automatically fall into the same category, making coordination and intent important considerations.

The report also warns that foreign actors could use prediction markets to amplify misleading political narratives or undermine confidence in election results. It does not identify a proven foreign operation manipulating the 2026 congressional markets, but argues that existing safeguards are difficult to assess without greater access to trading data.

Election Results Could Help Researchers Identify Misleading Odds

Once the votes are counted, ACDC plans to revisit markets where prices appeared to conflict with polling or other available information. Researchers hope to identify the trades responsible and determine whether particular accounts repeatedly pushed prices in the wrong direction.

Kendler-Kretsch said an unexpected bet is not necessarily a dishonest one. During the 2024 presidential election, large wagers on Donald Trump were eventually linked to a French trader whose own polling and research led him to believe Trump had a better chance of winning than other forecasts suggested.

The same difficulty applies to this year’s midterms. A trader might have better information than everyone else, might be hopelessly optimistic about a candidate, or might have another reason for placing a bet. The order book alone cannot settle that question.

For ACDC, the outstanding issue is how much of that activity can be independently examined. The election results will show which contracts paid out, but they will not reveal why the money was placed in the first place.

Kendler-Kretsch said the platforms hold information that could help researchers answer those questions. Until more of it becomes available, the industry’s claims about the reliability of election odds will remain difficult to test from the outside.

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