U.S. Rep. Chris Collins, R-N.Y., speaks to reporters as he leaves the courthouse after a pretrial hearing in his insider-trading case, in New York, Sept. 12, 2019.
U.S. Rep. Chris Collins, R-N.Y., speaks to reporters as he leaves the courthouse after a pretrial hearing in his insider-trading case, in New York, Sept. 12, 2019.

The first member of Congress to endorse Donald Trump for president resigned Monday a day before he is expected to plead guilty to stock fraud.

Republican Chris Collins of New York has been charged with securities fraud, conspiracy, wire fraud, and lying to the FBI.

Collins had planned to plead not guilty, but newspaper reports say he will change his plea when he stands before a judge Tuesday.

Collins is accused of using insider information that allowed his son, Cameron, and a third defendant, Stephen Zarsky, to avoid nearly $800,000 in stock losses in 2017.

According to the indictment, Collins had business ties to an Australian pharmaceutical company. He was at a White House picnic when the company's head e-mailed him that  tests for a new multiple sclerosis dug were a failure.

Collins is said to have almost immediately informed his son, who informed Zarsky. The two sold their shares in the company before the news was made public, allowing them to dodge nearly $800,000 in losses.

The value of the company’s stock plunged more than 90% after the news of the drug's failure was officially announced.

It will now be up to New York Governor Andrew Cuomo to call for an early election to fill Collins' vacant House seat.