Surprisingly strong corporate earnings, combined with a jump in home sales during March, sent the S&P 500 Index (^GSPC 0.87%) to its third straight day of gains. A brief panic caused by a fake tweet from the Associated Press roiled markets around lunchtime, but within minutes the tweet was exposed as the work of a hacker. Thankfully, claims that there was an explosion at the White House were patently false, and the S&P ended more than 1% higher, at 1578. But even the bullish sentiment of the day couldn't rally these three S&P components.

While rapid swings and unexpected news is par for the course on Wall Street, logic can be a little harder to find. Such was the case on Tuesday for shares of office supplies retailer Staples (SPLS), which slipped 4.5% on virtually no material news. The drop could be due to algorithm-based technical trading, as shares just crossed below their 200-day moving averages (apparently that's bad). With so little to substantiate today's weak performance, shareholders should take Tuesday's slip with a grain of salt. 

If you're a Cliffs Natural Resources (CLF 0.19%) investor, however, you may want to take a closer look at the company and its direction. Shares lost 1.9% today after the stock suffered a price target decrease at the hands of FBR Capital yesterday. A $2.5 billion company with $2.1 billion in debt on the books, Cliffs needs to start ponying up to its creditors before its shareholders can expect handsome rewards of their own.

Lastly, document management powerhouse Xerox (XRX) shed 1.9% on Tuesday after reporting earnings. While revenues were down slightly from a year ago, profits increased from $269 million to $296 million. Not bad, actually. But the real hit to the stock came from the company's forecasts. Headwinds in the document technology area have Xerox looking for earnings per share between $0.19 and $0.21 this quarter, a far cry from the $0.26 figure analysts expected.