Brendan McDermid/Reuters
The Securities and Exchange Commission, the top U.S. financial-markets regulator, says a cyberattack on its electronic system for storing public-company filings last year may have allowed for some illegal trading. In a statement issued late Wednesday, SEC Chairman Jay Clayton said the “incident” was caused by “a software vulnerability” in its filing system, though he did not provide further details on the scale of possible illicit trading caused by the breach. The hack was detected in 2016 but regulators only learned in August that some information obtained by the hackers may have led to illicit trading, Clayton said. The SEC, which stores the financial-disclosure documents of thousands of public companies and financial firms in its EDGAR filing system, said it is cooperating with the “appropriate authorities” in an investigation of the breach.