Andrew Harnik, Associated Press
This June 19, 2015 file photo shows the seal of the U.S. Securities and Exchange Commission at SEC headquarters, in Washington.

NEWARK, N.J. — Federal prosecutors say Ukrainian hackers worked with securities traders to make $30 million by breaking into the computer systems of companies that publish news releases about mergers and acquisitions.

According to a criminal indictment unsealed Tuesday, the defendants gained access to news releases and traded on the information in them before they were made public.

The hacking scheme allegedly raked in $100 million between 2010 and 2015. It is being called the biggest case of its kind ever prosecuted, and one that demonstrates yet another way in which the financial world is vulnerable to cybercrime.

The Securities and Exchange Commission also brought civil charges against the nine plus 23 other people and companies in the U.S. and Europe.