Dow Jones Industrial Average index closed lower on Wednesday as investors remained cautious regarding long term stability of Greece and several companies released earnings reports. Blue chip index fell 0.21% or 27.02 points to 12,938.67. Wal-Mart Stores posted the biggest loss for the index and extended its decline, giving up 2.5%. On Tuesday company reported disappointing 4th quarter profit. Hewlett Packard fell 1.4% after the firm posted a 44% drop in profit due to slowdown in PC sales.