Investors rewarded Walmart and punished Macy's after both released good news — here's why

Walmart and Macy's both had exceptionally good news for investors when they released their second-quarter earnings results this week. The sales, profit and individual store sales growth at both retailers were better than Wall Street analysts expected and Macy's even raised its forecast through the end of the year. The market reaction? Macy's shares spun into an almost free-fall, closing down 16 percent for the day while Walmart rallied up 9.3 percent. Here's why.