Late on Tuesday, the head of the Securities and Exchange Commission (SEC) Mary Jo White told a press conference: “This international scheme is unprecedented in terms of the scope of the hacking, the number of traders, the number of securities traded and the profits generated.”

According to SEC documents released on Tuesday, the hackers, starting in 2010, penetrated the computer servers of at least two newswire services and stole confidential earnings information for numerous companies traded on stock exchanges.

The information was gleaned from press releases that had not yet been released to the public. The hackers then used that stolen information to trade securities and to reap over $100 million in unlawful profits.

Two Ukrainian hackers, 23-year-old Aleksander Eremenko and 27-year-old Ivan Turchynov, both of whom reside in Kiev, Ukraine, are charged with perpetrating and operating the illegal scheme.

A group of stock traders, some of whom live in Kiev, and others who reside in the U.S., have also been charged. There are 32 defendants in total.

U.S.-based news wires that suffered the attacks included PR Newswire, Marketwired, and Business Wire, according to the SEC documents.

The group of hackers and traders built a large online business based on the information stolen from the press releases. Their website included an instructional video explaining on how the system made use of the information.

Authorities began making arrests on Tuesday. At the press conference, White said they have also seized a house boat, an apartment complex, a shopping center and a dozen other properties, as well as more than a dozen brokerage accounts.