Four international brokerage and management firms and six employees allegedly attempted to launder funds gained through fraudulent stock trading through offshore banks and the art world, including an attempted purchase of a Pablo Picasso painting, federal prosecutors and regulators announced Friday.

According to federal authorities, Panayiotis Kyriacou and Arvinsingh Canaye, managers at companies connected to Beaufort Securities Ltd. of London, along with accomplices at a number of management firms, conducted a number of schemes to defraud investors and launder funds for themselves and their clients.

In one scheme, begun in 2014 and lasting up until last month, the Beaufort defendants allegedly defrauded investors in U.S. companies by concealing the ownership stakes their clients had in those same companies. In a separate scheme, the Beaufort defenders allegedly opened brokerage accounts in the names of offshore shell companies with only nominee shareholders and directors, and proceeded to execute a pump-and-dump scheme that generated more than $50 million in proceeds for its clients, according to prosecutors.

Another alleged scheme, beginning even earlier in 2011, involved the Beaufort defendants and other co-conspirators laundering money by moving funds into accounts opened in the name of shell companies but controlled by clients of a defendant bank. The bank then provided the clients with debit cards, allowing them to withdraw cash that couldn't be traced. The funds were used to facilitate ongoing securities fraud, authorities allege.

Another scheme allegedly involved Kyriacou, his uncle and a London art gallery owner named Matthew Green. Authorities allege more than $9 million worth of ill-gotten money was to be laundered through the purchase and subsequent sale of artwork. According to an undercover agent involved in the process, Aristos Aristodemou, Kyriacou's uncle, proposed to purchase from Green Picasso's “Personnages, Painted 11 April 1965.” According to authorities, Aristodemou recommended the move because the art market remained the only one unregulated, and therefore was prime for money laundering attempts. The deal was ended before it could go through.

The firms—Beaufort Securities in London and its management services arm, offshore bank Loyal Bank, and offshore management companies in Mauritius and Trust Corp.—along with six connected individuals face criminal charges from the U.S. Attorney's Office for the Eastern District of New York.

In a separate action, the U.S. Securities and Exchange Commission brought charges against Beaufort Securities and Kyriacou over a pump-and-dump scheme that involved tech firm HD View and another firm. Regulators said an undercover FBI agent conspired with Kyriacou to use accounts at Beaufort to drive up the stock prices through promotions, manipulate it through matched trades and then sell for a profit.

Regulators said executives at HD View were involved in a separate scheme involving the undercover agent to generate false retail demand in exchange for trading proceeds. The two executives, Dennis Mancino and William Hirschy, were arrested and charged criminally as well, the U.S. Attorney's Office announced.

Information about counsel for the defendants was not available.