NEW YORK — Facebook plunged to its worst loss in four years Monday and led a rout in technology companies. The social media company’s stock fell following reports that a data mining firm working for the Trump campaign improperly obtained data on 50 million Facebook users.
The drop in Facebook stock came after the New York Times and the Guardian reported that the firm, Cambridge Analytica, was able to tap the profiles of more than 50 million Facebook users without their permission. Legislators in the U.S. and Europe criticized Facebook and said they want more information about what happened. Investors wondered if companies like Facebook and Alphabet will face tighter regulation as a result.
Daniel Ives, chief strategy officer and head of technology research for GBH Insights, said Facebook is in a crisis, and it will have to work hard to reassure users, investors and governments.
“This is a defining moment for them,” he said. “It either becomes a blip on the radar and it helps the platform mature … or it becomes the start of something broader.”
Elsewhere, the British pound rose and European stocks slumped after Britain and the European Union said they are getting closer to a deal that will complete Britain’s departure from the EU in March 2019.
The S&P 500 index sank 39.09 points, or 1.4 percent, to 2,712.92. The benchmark index took its biggest loss since Feb. 8, when it tumbled almost 4 percent as investors worried that rising inflation would slow the progress of the market and the U.S. economy.
The Dow Jones industrial average fell 335.60 points, or 1.3 percent, to 24,610.91. During the day it fell as much as 493 points. The Nasdaq composite gave up 137.74 points, or 1.8 percent, to 7,344.24. The Russell 2000 index of smaller-company stocks declined 15.49 points, or 1 percent, to 1,570.56.
Larger technology companies including Apple and Microsoft fared worse than smaller ones. Another market favorite, Amazon, also dropped, and health care stocks fell more than the rest of the market.
Representatives of Britain and the European Union said they made progress on the terms of Britain’s departure from the bloc. British envoy David Davis said important steps have been made in the last few days and he thinks EU leaders will back them in a meeting Thursday and Friday. Britain is scheduled to officially leave the EU on March 29, 2019.
The pound rose to $1.4050 from $1.3938. The British FTSE 100 index fell 1.7 percent and Germany’s DAX fell 1.4 percent. France’s CAC-40 was 1.1 percent lower.
Facebook said late Friday that it suspended Cambridge Analytica and its parent company. It said Cambridge obtained data from 270,000 people who downloaded a purported research app that was described as a personality test. A former employee said Cambridge was able to get data from tens of millions of other users who were friends with the people who downloaded that app.
