Shares of Facebook Inc. jumped on Thursday, with the social-networking giant on track for its biggest one-day pop in about five months, though it is also set to close out its worst month in three years. The stock FB, +3.83% gained 3.8%, which would represent its biggest one-day percentage gain since October. The move represents something of a rebound from heavy losses, as Facebook has been under heavy pressure following a controversy over how it has handled user data. For the month of March, it has lost 10.9%, its steepest monthly drop since March 2014. The Dow Jones Industrial Average DJIA, +1.06% rose 0.8% while the S&P 500 SPX, +1.17% was up 0.8% and the Nasdaq Composite Index COMP, +1.35% rose 0.9%.