Shares of Facebook (FB) plunged Monday to a 6.77 percent loss. The company’s value suffered as a result of reports over the weekend that the company shared personal information of users with a political analytics company.

Facebook’s stock opened the day at $185.09 before plummeting to as low as $170.72. Shares of Facebook closed at $172.56, marking a $42 billion loss in market value.

Facebook app Facebook's stock took a hit Monday following reports the company shared user data from millions of users. Photo: PDPics/Pixabay

The tumble for Facebook came as a result of a report that the company shared the data of as many as 50 million of its users with the controversial, United Kingdom-based political data analytics firm Cambridge Analytica—the same firm that helped the presidential campaign of Donald Trump in the 2016 election.

The controversy started in 2014, when a researcher at the firm collected user data through a third-party app that would ask users to take a personality test. The app was allegedly designed for academic research and users were required to connect their Facebook account in order to take the test.

About 270,000 people participated in the personality test and granted it access to their Facebook accounts. At the time, Facebook’s terms of service allowed the application to gather data from the friends of those who took the test. That allowed the app to collect raw data on as many as 50 million people without explicitly asking them for permission to share their information.

The researcher later provided that data to Cambridge Analytica, which may have used the information during the 2016 U.S. presidential election. The firm is owned in part by hedge fund billionaire and Republican donor Robert Mercer and was brought in to help the Trump campaign with its digital operations.

Former Cambridge Analytica employee and whistleblower Christopher Wylie told the Observer , “We exploited Facebook to harvest millions of people’s profiles. And built models to exploit what we knew about them and target their inner demons. That was the basis the entire company was built on.”

Bloomberg reported Facebook’s drop dragged down the stocks of other tech giants, including Twitter and Snap. The FANG group of companies—Facebook, Amazon, Netflix and Google—suffered as a result of Facebook’s controversy.