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.

Friday's Labor Department report showed somewhat stagnant growth in the jobs market, failing to live up to expectations. The 169,000 jobs added in August didn't convince investors that the U.S. economy could stand on its own two feet without continued stimulus from the Federal Reserve. The data had a neutral effect on the stock market: while the disappointing report was clearly bearish for America's recovery, it may mean continued stimulus from the central bank. At day's end, S&P 500 Index (SNPINDEX:^GSPC) added 0.1 points, or a healthy 0%, to end at 1,655.

First Solar (NASDAQ:FSLR) was one of the most pronounced decliners, slumping 2.4% just a day after logging 5.2% gains that earned it a spot as one of yesterday's 3 Best Stocks. Stock in the solar panel manufacturer, as you might guess, is extremely volatile, and can often jump or slump with no obvious catalyst behind the move. Down more than 70% in the last three years, but up more than 85% in the last 12 months, First Solar isn't for the conservative investor or the faint of heart. It may ultimately pay off more handsomely to wait and see how the solar industry develops and consolidates before taking a flier on this issue.

Tenet Healthcare (NYSE:THC), which owns hospitals, urgent-care centers, and other health facilities across the U.S. stumbled 2% Friday. Like First Solar, Tenet shares are highly volatile -- nearly 2.5 times more volatile than the S&P itself, actually. So when the $4 billion Tenet announced today that it was going to issue $4.6 billion in debt, investors cringed at the huge amount of additional leverage. And who's to blame them? The company's long-term debt/equity ratio already sits at 6.2; one can only hope Tenet's borrowing addiction is worth the short-term stress in the long run. 

Lastly, the communication technology company Harris (NYSE:LHX) shed 1.3% Friday. Investors can thank their lucky stars that Harris doesn't have the same debt concerns as Tenet; Harris's fall today was actually largely due to a fairly predictable cause that routinely pops up in the market. The stock went "ex-dividend" today, meaning that those selling shares Friday were still entitled to the company's next quarterly dividend. Short-term investors hungry for the next quarterly payout sell on the ex-dividend date, enjoying the guaranteed income stream without the risk of owning the stock.