(July 31, 2018, 1:51 PM EDT) -- NEW YORK — Shareholders filed a pair of securities class actions against social media giant Facebook Inc. and certain of its executive officers in New York federal court on July 27, alleging that the defendants concealed issues with Facebook’s revenue and user growth in violation of federal securities laws (James Kacouris v. Facebook Inc., et al., No. 18-6765; Fern Helms v. Facebook Inc., et al., No. 18-6774, S.D. N.Y.)....