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.

An hour before the opening bell this morning, jobless claims numbers for last week hit the Street. They showed claims falling from 351,000 to 331,000 for the week ending February 1. An hour later, the stock market did something it hadn't done much of this year: it rallied. In fact, the S&P 500 Index (^GSPC 0.03%) went on to post its best day of 2014, surging 21 points, or 1.2%, to end at 1,773.

 Of course, no matter how healthy the tree is, there are always a few bad apples. Chesapeake Energy (CHKA.Q) stock was just such an apple on Thursday, as shares tumbled 6.9% following an anemic 2014 outlook. Chesapeake Energy is, from an outside perspective, in an enviable position, being one of the top producers of natural gas in the U.S. But the domestic energy revolution is facing a setback this winter, as unusually harsh weather has hampered production at precisely the time when natural gas prices are spiking to highs not seen in the last five years. In other words, this is exactly the wrong time for production to start slumping. 

Another energy company, Tesoro (ANDV), also slipped big time today, losing 4.7%, as the refiner reported underwhelming earnings. Now, when I say "underwhelming," I really mean "horrendous." Analysts were calling for earnings per share of $0.31. Tesoro instead earned a measly $0.04 per share. The main culprit was dramatically reduced margins, which cratered more than 60% for fuel sales. Tesoro, which both refines oil and sells fuel at company-operated gas stations, was briefly and bizarrely forced by market conditions in California to buy fuel at high prices and then sell it for a loss. Not surprisingly, this business model produced disappointing results. 

Lastly, California-based biotech Gilead Sciences (GILD 1.06%) fell 2.1% Thursday, ending as one of the S&P's worst performers for a second straight day. Interestingly, Gilead Sciences actually reported blowout earnings late Tuesday, but shares have since sold off. That's because the stock market's all about expectations, and one of Wall Street's aspirations for Gilead is the success of its Hepatitis-C treatment Sovaldi. When the company failed to include Sovaldi sales projections in its outlook for the coming year, some shareholders got antsy and decided not to bet on the drug's success.