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

We haven't witnessed too many duck-and-cover days recently when it comes to U.S. economic data, but today was certainly a day to play ostrich, and hope for minimal downside in the broad-based S&P 500 (SNPINDEX:^GSPC).

Earlier this morning, the initial weekly jobless claims data was released, and it took everyone by surprise... in a bad way. Initial weekly jobless claims surged by 68,000, or 23%, to a seasonally adjusted 368,000. The spike in initial jobless claims could be a sign that the jobs market isn't as healthy as the recent drop to a 7% unemployment rate would indicate. However, it could just as easily be based on seasonal hiring fluctuations.

On the flipside, and also somewhat confusing, was the 0.7% rise in U.S. retail sales for the month of November. We've been witnessing ample struggles by retailers to move merchandise without heavy discounting of late, so it's a bit odd to see sales coming in so strong. It's also worth noting that this report was heavily influenced by strong auto sales.

As has been the story of late, better-than-expected GDP, unemployment, and retail sales figures would portend that the Federal Reserve is getting close to beginning to taper its monetary easing program known as QE3. While that does signify that the U.S. economy is strong enough to stand on its own, investors worry that this lack of stimulus (which partially comes in the form long-term U.S. Treasury purchases), could cause interest rates to rise. This would hurt the homebuilding and select banking sectors.

By day's end, the S&P 500 managed to claw its way back from an approximately 10 point deficit and finish lower by just 6.72 points (-0.38%), closing at 1,775.50, it's third-straight day of losses.

Topping the charts among thousands of stocks today was Arizona-based electric generation and delivery company UNS Energy (NYSE: UNS), which vaulted higher by 28.9% after Canadian electric utility Fortis agreed to buy UNS for $2.5 billion (excluding debt), or $60.25 per share, a 31% premium to yesterday's closing price. The deal is expected to close by the end of next year and should be earnings accretive to Fortis within the first year. With a buyout price of more than twice its book value, and five times trailing 12-month EBITDA, I'd say that UNS shareholders are getting a pretty fair premium for their shares.

Shares of highly volatile biopharmaceutical company Sarepta Therapeutics (NASDAQ:SRPT) rallied 19% on the day following potentially positive commentary from the Food and Drug Administration's director of Drug Evaluation and Research, Janet Woodcock. According to a MarketWatch report, Sarepta shares rocketed higher after today's Duchenne policy-forum from Parent Project Muscular Dystrophy, where Woodcock made her remarks about modernizing the pharmaceutical manufacturing process.

If you recall, Sarepta's lead experimental DMD drug, eteplirsen, was denied an accelerated new drug application filing following the dismal performance of a previously competing drug from GlaxoSmithKline (NYSE:GSK) and Prosensa (NASDAQ: RNA), drisapersen. With the FDA wanting to cover its bases with a larger confirmatory study, Sarepta is going to need to conduct a phase 3 trial to prove that eteplirsen is an effective treatment for a select type of DMD that accounts for 13% of all DMD cases.

Finally, low-to-mid-end jewelry chain Zale (NYSE: ZLC) advanced 15.5% after receiving a timely upgrade from Northcoast Research, which boosted its rating on the company to buy from neutral, with a $16 price target, representing 25% possible upside from yesterday's close. Zale has done a good job of driving traffic into its stores since nearly going bankrupt during the recession, but I still remain concerned that its debt levels are worrisome, given the potential for a very tough holiday season for retailers -- jewelers, especially.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.