Succeeds Rob Walton Who Will Continue to Serve as a Director FAYETTEVILLE, Ark., 2015-6-8 — /EPR Retail News/ — The Board of Directors of Wal-Mart Stores, Inc. (NYSE: WMT) today announced the election of Greg Penner, who previously served as the Board’s Vice Chairman, to the position of Board Chairman, effective at the end of today’s Shareholders’…