https://www.cnet.com/news/two-ukrainians-charged-with-2016-hack-of-sec/

"They targeted the Securities and Exchange Commission with a series of sophisticated and relentless cyber-attacks, stealing thousands of confidential EDGAR filings from the commission's servers and then trading on the inside information in those filings before it was known to the market, all at the expense of the average investor," Carpenito said.

SEC Chairman John Clayton revealed the hack in September 2017. At the time, Clayton said nonpublic information was transmitted through nonsecured personal email accounts.