Billionaire and notable health-care investor Phillip Frost was one of 10 individuals and 10 associated firms charged by the Securities and Exchange Commission on September 7 with participating in extremely profitable, yearslong pump-and-dump schemes.

Opko Health Inc. OPK, -5.28% , a pharmaceutical and diagnostics company that Frost founded and led as chairman and chief executive, was also named in the SEC complaint. Opko Health shares dropped 18% in extremely active September 7 trading before they were halted.

Frost, Opko and others were accused of making more than $27 million in stock sales proceeds between 2013 and 2018 by organizing large stock buys and promoting the stock — including through misleading articles and manipulative trading — while failing to properly disclose their stakes.

The scheme left public investors “holding virtually worthless stock,” according to the SEC complaint.

Related: SEC charges multiple firms, individuals with microcap fraud schemes, including Barry Honig

Frost, who is in his 80s and lives in Miami Beach, Fla., served as the chairman of generic drugmaker Teva Pharmaceutical Industries Ltd. TEVA, -2.37% for more than four years, stepping down in late 2014. He was previously chairman and chief executive of Ivax Corporation until 2006, when Teva acquired the company, and before that he worked to reformulate an old asthma drug into a best seller at Key Pharmaceuticals, which is now a subsidiary of Merck & Co. Inc. MRK, -0.37%

The Florida biotech billionaire also has a Miami science museum named after him, the Phillip and Patricia Frost Museum of Science. The SEC complaint in particular notes that he “enjoys a reputation as a successful biotech investor.”

Frost, for his part, denies the allegations, which he said in a statement last week “are belied by common sense, my history of supporting promising scientific technology, and the facts.”

Furthermore, the SEC did not provide him advanced notice before releasing the charges or an opportunity to answer questions, Frost said, something that it usually does.

“I invested in two of the entities identified in the complaint. These investments were made because I understood the entities presented promising medical developments and a real opportunity to deliver value for shareholders. I remain a significant long-term shareholder in both companies,” he said. “I intend to fight the charges that have been brought against me and will fight to clear my name.”

The biotechnology industry plays a sizable role in the SEC complaint. Frost and others allegedly approached a privately-held biotech company in 2010, proposing to take it public, as a way of financing research into a technology the company hoped to use in large drug markets.

The group merged the company with a publicly-traded shell company and effectively took over company management, but didn’t invest into the research and development that had been promised — leading to its abandonment, the SEC said. Meanwhile, in company filings, the group’s existence and majority share ownerships were not disclosed, according to the complaint, and one of the group’s members organized favorable articles that emphasized Frost’s role with the company and incorrectly said that its drug formulation was far along.

Related: Meet the perfect mark for a pump-and-dump scam: the modern retiree

According to a Seeking Alpha article that the SEC complaint references, that company was the microcap BioZone Pharmaceuticals, now a subsidiary of Cocrystal Pharma Inc. COCP, -9.40% , which saw shares drop 14.4% on September 7.

Another company allegedly used for a pump-and-dump scheme was a private company developing cancer therapies and diagnostics. Entities owned and controlled by Frost and others, including Opko, the privately-held Southern Biotech Inc. and Frost Gamma Investment Trust, for which Frost is a trustee, were involved, according to the complaint. In later filings, Frost and FGIT did not correctly disclose the nature of their stake, the SEC said.

That company was allegedly MabVax Therapeutics US:MBVX , according to the other Seeking Alpha article.

The scheme brought the company’s shares up from $1.91 to $4.30 and made the group more than $5.5 million, the complaint stated. Another effort, using another Seeking Alpha article, made the group more than $2.7 million, per the SEC complaint. MabVax had shares drop 9.6% to 45 cents on September 7.

Florida investor Barry Honig, John Stetson, Michael Brauser, John R. O’Rourke III, Mark Groussman, Elliot Maza, Robert Ladd, Brian Keller, John H. Ford, Alpha Capital Anstalt, ATG Capital LLC, GRQ Consultants Inc., HS Contrarian Investments LLC, Grander Holdings Inc., Melechdavid Inc. and Stetson Capital Investments Inc. were also named in the SEC complaint.

The SEC is requesting that the defendants be required to give up their “ill-gotten gains,” with interest, as well as civil penalties, and that they be barred from other penny-stock offerings.