Facebook stock plunged Monday after the Federal Trade Commission (FTC) announced it was investigating the social media company over a data breach affecting roughly 50 million people.

Shares in Facebook fell more than 6 percent, roughly $10, after the FTC confirmed it was probing the company over potential violations of a 2011 settlement regarding the use of customer data.

"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," the FTC said in a statement.

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The social media company has been mired in controversy over reports that Cambridge Analytica, a political firm that worked on President Trump Donald John TrumpBubba Wallace to be driver of Michael Jordan, Denny Hamlin NASCAR team Graham: GOP will confirm Trump's Supreme Court nominee before the election Southwest Airlines, unions call for six-month extension of government aid MORE’s 2016 campaign, used data from roughly 50 million Facebook users without permission.

Facebook’s stock price has fallen close to 20 percent since the start of last week, dropping from $185 on March 16 to less than $150 on Monday.

While U.S stocks took heavy losses last week, they surged across the board Monday over news of trade talks between the Trump administration and China. The Dow Jones industrial average spiked close to 1.2 percent, while the Nasdaq and the S&P 500 rose just less than 1 percent.

Growing fears of a trade war shook Wall Street last week as Trump announced up to $60 billion in tariffs on China as a response to intellectual property theft from U.S. companies. The Dow dropped 11.6 percent from its 52-week high, entering a formal correction, while the S&P lost 5.9 percent. The Nasdaq lost 6.5 percent on the week.