Republican New York Congressman Chris Collins has resigned from Congress amid reports he plans to plead guilty to charges of insider trading.
According to prosecutors, Mr Collins gave confidential information about an Australian biotechnology firm to his son.
He had called the charges “meritless” and pleaded not guilty, but will reportedly change his plea on Tuesday.
Mr Collins’ upstate New York district is overwhelmingly Republican.
He was able to win his re-election campaign last year despite facing charges of securities and wire fraud, and of making false statements to FBI investigators.
According to a spokesman for Speaker of the House Nancy Pelosi, Mr Collins on Monday submitted his letter of resignation which will take effect on Tuesday.
According to US media, Mr Collins will change his plea to guilty during a hearing in a Manhattan court on Tuesday. It’s unclear if he will plead guilty to the original charges against him or another set of charges.
Mr Collins was one of the first mainstream Republicans to endorse Donald Trump’s presidential candidacy.
He was arrested by the FBI last August after prosecutors alleged that he alerted his son to a failed drug trial, allowing him to divest and avoid more than $500,000 (£406,000) in losses.