The prediction market Kalshi on Monday fined the Republican nominee in a competitive House race and imposed its first-ever lifetime ban, against former Rep. George Santos, after insider trading investigations.

The North Carolina candidate, Laurie Buckhout, admitted in a statement to CNN that she bet on her own campaign and said she made a “dumb mistake.”

This is the highest-profile example to date of political insider trading, where candidates or staffers trade on markets where they possess inside information or can influence the outcome. Experts have warned the practice is a growing danger as prediction platforms have exploded in popularity this year.

“I bet on myself. Literally,” Buckhout said. “It was a dumb mistake, and as soon as I learned there was an issue, I worked to make it right. Safe to say my career as a Kalshi trader was short-lived.”

Kalshi noted in a legal filing on Monday that she traded less than $1,000, cooperated with their internal investigation, and will get a three-year suspension.