The U.S. Securities and Exchange Commission has charged 21 individuals in connection with an alleged insider trading scheme that ran for approximately a decade.

The SEC said the scheme centered on confidential information taken without authorization from multiple global law firms. Those firms were used as sources of non-public data that participants then allegedly traded on for financial gain.

According to the SEC, the operation generated millions of dollars in illicit proceeds over its run. The commission announced the charges as part of its enforcement action against all 21 named defendants.

The SEC said the misappropriated information originated from several law firms operating internationally, though it did not limit the alleged conduct to any single jurisdiction. The breadth of the scheme, spanning roughly ten years and drawing on multiple firms as sources, formed the basis of the commission's case against the defendants.