Cybercriminals compromised the U.S. Securities and Exchange Commissions Electronic Data Gathering, Analysis and Retrieval (EDGAR) system in May 2016. Malicious actors could have used these documents as the basis for insider trading. Security breach disclosure was vague enough that experts have begun speculating about potential nation-states or hacktivist groups as the instigators. The agency is investigating this matter internally and cooperating with law enforcement. But improvements are possible in post-breach responses, but the SEC dropped the ball on the second, determining the type of data stolen.”]
Source: https://securityintelligence.com/news/billion-dollar-security-breach-unpacking-the-sec-compromise/