Americans can turn their predictions about who will control Congress into a bet, but most don’t think they should. With the midterms approaching, 60% of U.S. adults oppose using prediction markets to wager on election results, while 13% support it and 24% are unsure, according to a Reuters/Ipsos poll provided to Fortune.
They’ll see the odds anyway. CBS News said Sept. 30 it would add real-time prices from Kalshi to its midterm coverage, alongside its own polling. Kalshi has similar deals with CNN and CNBC, and it licenses vote counts and race calls from the Associated Press. CBS News and CNN now share an owner: Skydance, which completed its purchase of CNN’s parent, Warner Bros. Discovery, on Oct. 6.
Those prices can rest on a small number of traders. On Polymarket’s global platform, the top 1% of wallets account for 68% of trading volume on 2026 congressional markets, and 80% of those markets have fewer than 100 wallets trading, according to an August analysis by the Anti-Corruption Data Collective, a nonprofit research and advocacy group.
The opposition crosses party lines, with 69% of Democrats and 61% of Republicans opposing election betting. Three-quarters of Americans consider prediction-market wagering a form of gambling. Only 7% of respondents said they had used a prediction market to bet money.
“Most view prediction markets as a form of gambling, and it’s clear that they do not see elections or government decision-making as appropriate subjects for it,” Alec Tyson, a senior vice president and lead pollster at Ipsos U.S. Public Affairs, told Fortune.
Ipsos surveyed 4,506 U.S. adults from Sept. 30 through Oct. 5. The margin of sampling error is plus or minus 1.5 percentage points.
But monthly global trading volume and public approval measure different things. Sports offer what elections struggle to match: frequent events and fast-changing odds that give people more reasons to trade, said Dustin Gouker, a gambling industry analyst and author of the prediction market newsletter The Event Horizon.
A poll or campaign development can move an election market. A sports game can move odds and produce those shifts within minutes as teams score and leads change.
“I don’t think it’s necessarily that election trading isn’t popular,” Gouker told Fortune. “It’s more that it doesn’t feature some of the things that we see in these markets that are seeing more volume.”
Combined monthly trading volume on Kalshi and Polymarket more than doubled, from about $26 billion in May to $53 billion in July, according to a September Pew Research Center analysis. Sports drove most of that increase. Users buy and sell contracts on whether an event will happen; winning contracts pay $1 and losing ones pay nothing.
Those totals cover all trading and count contracts at their potential $1 payout rather than their purchase price. They don’t represent company revenue or the cash traders spent.
Kalshi challenges the findings
Kalshi called the poll biased, challenging how it described prediction markets and asked about wagering on government events.
“It’s not hard to bias a poll and this poll is biased,” a Kalshi spokesperson said in a statement to Fortune. “Ask leading questions about whether people support ‘betting on war,’ and you’ll get the answers this poll arrived at. Kalshi doesn’t even offer war markets.”
The questionnaire didn’t use the word “war.” It described prediction markets as allowing people to “wager money on the outcome of real-world events.” It then asked separately about elections, military actions, government policy decisions, and sports and did not measure familiarity. A March Ipsos poll for the American Institute for Boys and Men found just 21% of Americans were very or somewhat familiar with prediction markets.
“We welcome research on our industry, but a clearer picture would come from research that measures familiarity, uses neutral wording, and reports all responses,” Kalshi said.
Ipsos did not respond to Kalshi’s criticism by publication time.
Traders sued Kalshi earlier this year in March over its handling of a market on whether Iran’s supreme leader, Ali Khamenei, would leave office. The dispute followed his killing in U.S.-Israeli strikes. Kalshi told Reuters at the time that the rules excluded death-related outcomes and that it had reimbursed trading fees and net losses.
Election odds aren’t election results
Polymarket argues that its audience extends beyond bettors. More than 90% of visits are to view markets rather than trade, a spokesperson told Fortune. “Prediction markets are a way to get unbiased, accurate information about the events that impact our lives,” the spokesperson said.
Gouker said election markets attract viewers by distilling polls and news into a probability, but turning those visitors into traders is a separate business challenge. He expects election trading to pick up as the midterms approach, though doubts it will get to the level of sports betting. He also expects the 2028 presidential election to draw more trading than this year’s midterms.
He cautioned against treating high odds as a call of the race. Gouker pointed to Abdul El-Sayed’s Michigan primary, saying markets showed him as an overwhelming favorite around the close of voting before incoming results suggested a closer contest. El-Sayed led by just under one percentage point when the Associated Press called the race.
A candidate with a 70% chance of winning still has a 30% chance of losing. To judge a market’s accuracy, Gouker said, look at whether outcomes occur as often as the odds suggest: “When a market says something should happen, it happens roughly the amount of times we would expect it to.”
He added, “You have to look at them as probabilities and not as these crystal balls.”
