Prediction Markets Flip Toward Acton in Ohio

Prediction markets shifted sharply toward Amy Acton over Vivek Ramaswamy in Ohio's governor race.

Republican Vivek Ramaswamy has lost his lead over Democrat Dr. Amy Acton in two prediction markets as Ohio's governor race enters its final stretch. As of August 28, Polymarket put Acton's chance of victory at 54 percent to Ramaswamy's 47 percent on about $173,000 in volume, while Kalshi showed Acton ahead 55 percent to 45 percent on nearly $1.4 million traded. Both markets had priced the contest as essentially even only days before August 24, when traders moved sharply toward Acton.

The reversal is striking because of the money gap. According to Signal Ohio, Jeffrey Yass made a fresh donation of at least $10 million to V-PAC, adding to $20 million he previously gave, meaning one billionaire has now given more to support Ramaswamy than Acton has raised from all donors combined ($21.8 million). Ramaswamy and his allies have spent or reserved $82.3 million on TV and digital ads this year, compared with $11.1 million in expected pro-Acton spending, per Medium Buying data cited by Signal Ohio. Yet that seven-to-one advantage has not produced a clear lead.

Polling remains far closer than the market shift suggests. A Fox News poll conducted August 6 to 10 among 1,008 registered voters put Ramaswamy ahead 50 to 48, within the plus-or-minus 3-point margin of error. A Tulchin Research survey found Acton leading 46 to 44, a New York Times/Siena poll had them tied at 47, and an AARP survey gave Acton a 47-to-44 edge. Taken together, the surveys point to a race too close to call, mixing registered- and likely-voter samples.

Ohio has moved firmly toward Republicans in presidential elections—President Trump carried the state by 11.2 points in 2024—but the open-seat race to succeed term-limited Governor Mike DeWine tests whether that realignment extends down the ballot. Acton's competitiveness means both parties may need to devote money and organizational resources to a state Republicans might once have expected to defend comfortably. Acton has framed the race around affordability, while Ramaswamy promises to be "the most conservative governor this state has ever seen," campaigning on lower property taxes and a phased end to the state income tax.

Prediction markets can absorb new information faster than conventional polling, but thin trading and large transactions mean the prices should not be treated as forecasts, as Newsweek cautions. Polling and market prices may diverge again as voters react to advertising, debates and late developments before the November 3 election. According to Signal Ohio, most pro-Acton advertising—including a $9.4 million campaign funded by the Democratic Governors Association—is set to begin after Labor Day, meaning the spending gap could narrow just as the market momentum favors her.