A top House Democrat, Rep. Louise Slaughter of New York, called Collins’ action “a disgrace to Congress.” Collins responded that Slaughter is on a “witch hunt.”

Collins — who has repeatedly denied any improper or unethical behavior — is on the board of Innate and is its biggest stockholder, having invested at least $6 million in the firm. His children own a block of Innate shares too.

Collins has pushed the company’s stock to former HHS Secretary and one-time House colleague Tom Price, other lawmakers and officials in Buffalo, N.Y. Collins was once overheard bragging on the phone in the House Speaker’s Lobby about “how many millionaires I’ve made in Buffalo the past few months.” Price made more than $225,000 in his Innate stock trades, according to public records.

Both Price and Innate officials refused to cooperate with OCE’s probe, although Innate did provide information to Collins to help him respond to the ethics watchdog’s inquiries. OCE lacks subpoena authority and cannot compel witnesses to testify or produce documents. The Ethics Committee, however, does have that power.

OCE looked into allegations that Collins got insider information on Innate’s stock, as well as an opportunity to purchase it at a discount. And Collins reportedly introduced legislation that could have benefited Innate.

The OCE investigators determined “there is a substantial reason to believe that Representative Collins shared material nonpublic information in the purchase of Innate stock, in violation of House rules, standards of conduct, and federal law.”

OCE also found that “there is a substantial reason to believe that Representative Collins took official actions or requested official actions that would assist a single entity in which he had a significant financial interest, in violation of House rules and standards of conduct.”

OCE, though, said Collins had not purchased Innate stock at a discounted rate.

According to OCE, “Representative Collins frequently updated Innate shareholders on the company’s activities, financial status, business strategies, and industry news. The OCE identified examples of the type of communications Representative Collins made to U.S. investors containing public and nonpublic information.”

Collins also spoke about an Innate drug during a committee hearing with a top NIH official in 2013 without disclosing his involvement with the company. Collins later discussed the drug with other NIH officials and “requested that an NIH researcher meet with Innate’s chief science officer,” according to OCE. By that time, NIH officials had been made aware of Collins’ ties to Innate.

Collins continues to insist he has done nothing wrong in his dealings with Innate.

“There’s nothing of substance there at all,” he told reporters at the Capitol. “I have followed all ethics guidelines since Day One including them reviewing everything I own and making sure it was structured from the day I walked in. … I have done everything anyone could possibly do.”

Collins said his lengthy private-sector career helped him get elected to Congress but that inherently “some issues arise.” He added that he’s “disappointed” the Ethics Committee didn’t totally dispense with the matter, noting that they often leave charges hanging over members for years.

Collins also ripped OCE.

“They have no authority. They cannot subpoena,” he said. “You may say they’re not political but I would disagree with that. They do not follow the even legal procedures.”

Slaughter, who had called for an investigation into Collins and has long sought tough restrictions against insider trading by lawmakers, said his constituents “deserve better.”

“The Office of Congressional Ethics has found clear and convincing evidence that Congressman Collins likely broke federal law,” she said in a statement. “He put his obsession to enrich himself before the people he swore to represent. It is a disgrace to Congress and to his constituents, who deserve better.”