The Federal Trade Commission confirmed Monday it's investigating Facebook's data practices.
The department released a statement that says, in part: "The FTC takes very seriously recent press reports raising substantial concerns about the privacy practices of Facebook. Today, the FTC is confirming that it has an open non-public investigation into these practices."
Facebook's deputy chief privacy officer told CNBC the company appreciates "the opportunity to answer questions the FTC may have."
The social media giant's shares fell about 5 percent at one point after the FTC announcement.
The investigation comes after news that Cambridge Analytica accessed about 50 million Facebook users' information without their explicit consent.