GameStop (GME) -8.5% after Wal-Mart (WMT) rolls out discounts on top video games. "Many of the GameStop stores overlap in close proximity to a Wal-Mart store, as GameStop has historically sought to benefit from Wal-Mart's foot traffic," analyst Tony Wible notes. Gaming stocks are also under pressure: NTDOY.PK -3.7%. ATVI -2.3%. SNE -2%.