While the U.S. Securities and Exchange reportedly investigates whether Yahoo Inc. should have disclosed two massive data breaches to investors earlier, corporate defense attorneys who are not involved with the matter say any charges would mark the first SEC case involving failure to disclose a data breach to shareholders.

The investigation, reported first by The Wall Street Journal, will examine whether Yahoo broke securities laws when it waited until 2016 to disclose two data breaches in which more than a billion users had their data compromised.

Yahoo declined to comment on the reports of an SEC investigation beyond a November 2016 10Q securities filing in which the company said it is "cooperating with federal, state and foreign government officials and agencies seeking information and/or documents" about the breach, including the SEC. The commission also declined to comment Monday.