Rep. Christopher Collins (R-NY) resigned his seat in Congress on Monday, a day before he is expected to plead guilty to felony charges of insider trading.

Collins notified House Speaker Nancy Pelosi in a letter that he will end his term ”effective immediately.” Collins, 69, is scheduled to appear in federal court on Tuesday and change his plea from not-guilty in a case brought by the Justice Department.

Federal prosecutors in Manhattan charged Collins in 2018 with illegally trading on material non-public information on a pharmaceutical company. Collins allegedly told his son to dump stock in Innate Immunotheraputics after learning the Australian company’s only drug failed a clinical trial—information that was not yet public. Collins’s son, Cameron, and his father-in-law were also charged with insider trading for allegedly dumping Innate stock on the congressman’s tip.

The congressman was narrowly re-elected to a fourth term last year after promising to fight the charges in court. Earlier this month, he lost several important pre-trial motions, including an attempt to use the Constitution’s protection of “speech and debate” by members of Congress to cover the alleged insider trading conversations.

Collins, a Buffalo-area millionaire, was deeply involved in Innate for years, sitting on its board of directors and owning several million shares of stock. Collins and his family and associates at one point owned almost one-third of the company, as The Daily Beast previously reported.

“Do you know how many millionaires I've made in Buffalo the past few months?” Collins was overheard saying on the House floor in early 2017.

Among those who bought Innate stock, at a steep discount, were four fellow congressman including Tom Price, who subsequently served as Secretary of Health and Human Services in the Trump administration.

Collins participated in the company’s initial-public offering in Australia—a Daily Beast revelation that led Congress to close a loophole that had allowed lawmakers to be involved in foreign IPOs. He also promoted legislation that could have benefitted Innate’s U.S. prospects, as The Daily Beast previously reported.

The non-partisan Office of Congressional Ethics in 2017 found evidence Collins violated House rules and federal law by sharing material non-public information with members of Congress and using his office to advance Innate’s interests, such as asking an employee of the National Institutes for Health to meet Innate employees about drug trials.

OCE recommended Collins be investigated by the House Ethics Committee, but the committee said this spring it would not begin investigating until Collins’s criminal trial was concluded.