https://www.reuters.com/article/us-facebook-cambridge-analytica-ftc/facebook-shares-tumble-as-u-s-regulator-announces-privacy-probe-idUSKBN1H2212 >Shares of Facebook Inc fell more than 5 percent on Monday after the U.S. consumer protection regulator made public its investigation of how the social network allowed data of 50 million users to get into the hands of political consultancy Cambridge Analytica.