Greg Mulholland, a penny-stock promoter, pleaded guilty to conspiring to manipulate stocks and laundering over $250 million in profits. Prosecutors are calling it one of the biggest pump-and-dump schemes of all time.

A pump-and-dump scheme is the fraudulent practice of encouraging investors to buy shares in a company in order to inflate the price artificially and subsequently selling one’s own shares while the price is high.

Gregg R. Mulholland pleaded guilty in Brooklyn federal court to manipulating over 40 publicly traded companies, including Cynk Technology Corp., whose stock’s climb and subsequent collapse in 2014 briefly gave the social-network operator a $4 billion valuation even though it reported no assets, no revenue and just one employee.

Mulholland faces up to 20 years in prison for the pump-and-dump scheme, according to the Brooklyn U.S. Attorney’s office.

Prosecutors alleged Mulholland ran a broker-dealer called the Mulholland Group, which used shell companies in Belize and Nevis to conceal ownership in the stock of U.S. public companies. Between 2010 and 2014, Mulholland fraudulently promoted stocks to investors, while concealing his ownership of the companies. After driving up the value of the stocks, Mulholland would sell off his shares and launder the proceeds through a network of offshore entities, according to prosecutors.

“Mulholland’s staggering fraud perpetrated on the investing public was built on an elaborate offshore shell game,” Brooklyn U.S. Attorney Robert Capers said in a statement after the guilty plea. “Through manipulative trading, Mulholland generated profits of more than $250 million and used a corrupt lawyer to launder the proceeds into the United States.”

FBI agents arrested Muholland in July at Phoenix International Airport during a layover in a flight trip from Canada to Mexico. He was ordered jailed pending Brooklyn federal court hearings in the criminal case.

Mulholland’s plea agreement requires him to forfeit a Dassault-Breguet Falcon 50 corporate jet, a Range Rover Defender all-terrain vehicle, two real estate properties in British Columbia, Canada and funds and securities in more than a dozen bank and brokerage accounts.

If you or someone you know has lost money as a result of a broker’s wrongdoing, please contact Richard Frankowski at 888-741-7503 to discuss your potential legal remedies or complete the contact form.