Early movers: MDVN, PFE, CST, ISIL, SYT, FB, VIAB, VLKAY, JPM, MAT & more By: CNBC.com News August 22, 2016 at 07:48 AM EDT These are the stocks posting the largest moves before the bell. Read More >> Related Stocks: Discover Financial Services Facebook JPMorgan Chase & Co L Brands Marathon Oil Mattel Office Depot Pfizer Via Renewables Inc Cl A Viacom Zoetis