* Wal-Mart shares fell 2.5 percent to $70.09 in premarket trading after the Dow component reported weaker-than-expected quarterly earnings and lowered its full-year forecast. * U.S. oil prices and industrial metals, including copper, also traded near six-year lows, adding to the bearish market sentiment amid worries over China’s growth outlook. * Wall Street closed higher on Monday after strong economic data boosted the housing sector and as investors bought recently battered shares in biotech and media.