F.T.C. Investigating Facebook in Use of Personal Data by Firm Tied to Trump

The Federal Trade Commission has opened an investigation into whether Facebook violated an agreement with the agency on data privacy, after reports that information on 50 million users was improperly obtained by the political consulting firm Cambridge Analytica, according to a person with knowledge of the inquiry.

The investigation, started in recent days, adds to the mounting pressure against Facebook in the United States and in the United Kingdom about its handling of the data. Cambridge Analytica used the information to help President Trump’s presidential campaign profile voters during the 2016 election.

The F.T.C. and Facebook reached a settlement in 2011 after the agency accused the company of deceiving customers “by telling them they could keep their information on Facebook private, and then repeatedly allowing it to be shared and made public,” according to a statement at the time.

Among several violations, the F.T.C. found that Facebook told users that third-party apps on the social media site, like games, would not be allowed to access data. But the apps, the agency found, were able to obtain almost all personal information about a user.

“We are aware of the issues that have been raised but cannot comment on whether we are investigating,” a F.T.C. spokeswoman said in a statement on Tuesday. “We take any allegations of violations of our consent decrees very seriously.”

Senators Amy Klobuchar, a Democrat from Minnesota, and John Kennedy, a Republican from Louisiana, have asked to hold a hearing on Facebook’s links to Cambridge Analytica. Republican leaders of the Senate Commerce Committee, led by John Thune of South Dakota, wrote a letter on Monday to Mark Zuckerberg, Facebook’s chief executive, demanding answers to questions about how the data was collected and if users were able to control the misuse of data by third parties.

“The possibility that Facebook has either not been transparent with consumers or has not been able to verify that third party app developers are transparent with consumers is troubling,” Mr. Thune said in the letter.

On Tuesday morning, a committee within the British Parliament sent a letter to Mr. Zuckerberg asking him to appear before the panel to answer questions on the company’s connection to Cambridge Analytica.

“The committee has repeatedly asked Facebook about how companies acquire and hold on to user data from their site, and in particular about whether data had been taken without their consent,” wrote Damian Collins, chairman of the British committee. “Your officials’ answers have consistently understated this risk, and have been misleading to the committee.”