Wisconsin Elections Commission Chair Ann Jacobs is warning voters that it’s against state law to wager on an election if you are casting a ballot in that race. 

Jacobs’ comments, made last week on X, come as prediction market sites such as Kalshi and Polymarket have continued to grow in popularity. 

“I know it’s all the rage to bet on everything, but you cannot bet on an election in Wisconsin,” Jacobs wrote. “If you do, your ballot can be challenged & thrown out … So go vote and save your $ for playing Euchre with your uncle!” 

Wisconsin’s election laws include a provision that states nobody “shall be allowed to vote in any election in which the person has made or become interested, directly or indirectly, in any bet or wager depending upon the result of the election.” 

Currently on Kalshi, tens of thousands of dollars in bets have been placed on the result, turnout and margin of victory of next week’s state Supreme Court election. Even more money has been wagered on the state’s upcoming race for governor — including $85,000 on the Democratic primary race. 

The ethics of participating in prediction markets have come under scrutiny as their popularity has grown, particularly the opportunity for placing bets that are akin to insider trading. More than $500 million in bets were placed on the prospect of the U.S. going to war with Iran shortly before major announcements about U.S. military actions in the country, NBC News reported. 

The law against betting on elections has been on the books in some form since 1849. Other states, including Arizona and Texas, also have laws against wagering on elections. 

Jacobs told Wisconsin Public Radio that the state isn’t going to go looking for offenders of the election betting law, however if someone brags online about a big win, that could open them up to scrutiny and the potential cancellation of their vote. 

“No, the state is not going out and issuing search warrants to betting platforms to cross reference against voters,” Jacobs told WPR. “I think the most likely way this would come up would be exactly how you think, which is somebody posted on social media saying, ‘Hey, I made this big bet,’ and then someone who doesn’t like them reports it to the authorities.”

Jacobs told the Wisconsin Examiner a voter’s ballot could be voided because of betting through the state’s existing ballot challenge processes, which allow anyone to object to the counting of an absentee ballot. She compared it to challenges that are received for people who post selfies with their ballots.

“Who would do such a thing? people who hate you,” Jacobs said. “It’s almost always the opposing candidate. Is that a lot of work? Yes. Is it sort of silly? Yes. If you think you’re going to get a big amount of money, then don’t vote.”

The emergence of the prediction markets was also an impetus for the state Legislature quickly passing a bill to legalize online sports betting in Wisconsin. That bill is currently awaiting the signature of Gov. Tony Evers.