Election prediction markets tilted heavily toward Vice President Kamala Harris overnight after a bombshell poll released Saturday showed her leading former President Donald Trump in Iowa.

A Des Moines Register/Mediacom Iowa Opinion poll found the Democratic candidate leading her Republican opponent by three points among likely voters, 47% to 44%.

The poll was conducted by highly respected pollster Ann Selzer, who has a long track record of producing results that are eerily reflective of the final election results.

“It is incredibly brave to publish this survey” said Nate Silver, the statistician and election data guru, in a tweet. “So Harris won't be ahead in our forecast because there was another poll in Iowa today that was good for Trump. But I wouldn’t want to play poker against Ann Selzer.”

Selzer's stature — coupled with the prevailing wisdom that Iowa, which he represented in 2016 and 2020, should be a safe state for Trump — was enough to send the betting markets that have largely favored Trump into a frantic correction.

Kalshi gave Trump a 55 percent chance of victory on Saturday, but that had dropped to 50 percent by early Sunday morning in a dead heat with Harris.

Kalshi's betting market gave Trump a remarkable 64 percent chance of winning as recently as Wednesday. Over $174 million was traded on the platform related to the election.

Trump's chances of victory were at times 63 percent on Saturday Polymarketbut fell seven points to 56 percent on Sunday morning, with Harris at 44 percent.

Another betting service, Predict itwhich began pricing in a narrow Harris victory on Friday, gave her more breathing room after the Iowa poll.

In the meantime, Election betting odds— a website that tracks and analyzes election prediction markets Kalshi, Polymarket and PredictIt, as well as Betfair and Smarkets — gave Trump a 52 percent chance of winning the Electoral College on Sunday, down from 4.4 percent in the final day.

Harris was nearly 47.5 percent higher in the site's model the week the Trump campaign staged a crazy, racist rally at Madison Square Garden that even many elected Republicans condemned for its crass, boorish tone 10 points up.