Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The S&P 500 Index (^GSPC -0.46%) fell again today, losing ground in three straight sessions for the first time since June. For anyone worrying that they missed some terribly important and downbeat news sparking a Wall Street sell-off, don't worry: There was none. In fact, yesterday's trade data was surprisingly upbeat and should boost second-quarter GDP growth when it comes out. Alas, in the eyes of Wall Street this merely means an end to the Fed's loose money policies may come sooner rather than later. With that in mind, the S&P lost 6 points, or 0.4%, to end at 1,690.

A good way to punish your stock price is to, firstly, go into business in an industry that hasn't even proven itself as commercially viable. You'll want to set expectations pretty high because, hey, there's nowhere to go but up, right? Then you'll want to miserably underperform those expectations. Such is the story of First Solar (FSLR -1.39%), or at least the story of its second quarter. The stock plummeted 13.4% after sales plunged 46% from a year ago, profits took a 70% hit, and the company lowered its outlook for the current year. 

Third-party logistics company CH Robinson Worldwide (CHRW -0.96%) also did a fine job of disappointing its shareholders today, slumping 5.5% after an earnings miss of its own. While the decline certainly would have been steeper if its revenue and earnings had crumbled, as First Solar's did, the air and freight delivery company saw sales rise 11%, though its earnings did fall slightly in the quarter. Today's slide is only the result of slightly underperforming analyst expectations, so shareholders needn't get too concerned about the health or viability of the business itself.

Lastly, Marathon Oil (MRO 0.76%) shares dropped 4.8% after it also failed to deliver on quarterly results. The oil and gas company, which spun off its refinery division two years ago, is now more sensitive to fluctuations in energy prices. Oil sands mining took a step back in the most recent quarter as the company dealt with larger-than-expected downtime. On top of the earnings miss, Bank of America also downgraded the stock to a neutral rating, while oil futures fell nearly 1% Wednesday.