The US has charged ten defendants, including two Ukrainian hackers, for their roles in the 2016 breach of a key government financial database.
Authorities said the hackers broke into the corporate filing system, gaining confidential information on dozens of companies.
They said the files were sold to traders, who used it to make more than $4.1m (£3.2m) in illegal profits.
The US said those gains came at the “expense of the average investor”.
The Department of Justice identified the hackers as Oleksandr Ieremenko and Artem Radchenko.
The Securities and Exchange Commission also charged two traders in California, one in Russia, and three in Ukraine, as well as two companies for violations of securities laws.
Lawyers for those charged could not be reached.
In 2015, the US charged some of the same men in a hack of newswire services, which generated more than $100m.
Tuesday’s complaints focus on a 2016 hack of the SEC’s Edgar database, an important government repository for corporate announcements.
They concern trades made between May 2016 and October 2016, the SEC said.
The SEC disclosed the hack in 2017.
On Tuesday, Stephanie Avakian, co-director of the SEC’s enforcement division, said international computer hacking schemes post an “ever-present” risk.
She said: “Today’s action shows the SEC’s commitment and ability to unravel these schemes and identify the perpetrators even when they operate from outside our borders.”