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.

After reaching all-time highs just a week ago, the benchmark S&P 500 Index (SNPINDEX:^GSPC) was unable to maintain its lofty valuation in the first full week of August trading. The index fell six points, or 0.4%, on Friday, ending at 1,691, as Wall Street worried that the Federal Reserve would scale back on quantitative easing efforts in short time. But if you think this week's 1.1% S&P decline is bad, just check out what three of its components did today alone. You'll feel better. 

J.C. Penney (NYSE:JCP) underperformed 499 other stocks to claim the throne as the worst performer Friday, slumping 5.8%. The once-esteemed department store chain is -- in simple terms -- now an absolute nightmare. After advocating for the appointment of CEO Ron Johnson in 2011, hedge fund manager Bill Ackman advocated for the re-appointment of former CEO Mike Ullman earlier this year. Just four months later, Ackman is once again crying for a new CEO after another of his own nominees has failed to live up to his standards. You can certainly understand investors wanting to distance themselves from such mercurial ownership interests. 

The network equipment maker Juniper Networks (NYSE:JNPR) lost 5.6% today, not because of an idiotic hedge fund manager who can't make up his mind, but because the company is under investigation for bribing foreign officials. At this stage, it remains nothing more than an investigation by the SEC and the U.S. Department of Justice, and there's a possibility that the company could be absolved of any wrongdoing. For the time being, however, the news simply represents increased risk for investors with no added reward potential -- never a good combo for shareholders. 

Electric-utility company Entergy (NYSE:ETR) dropped 3.3% Friday after withdrawing a proposal before the Texas Public Utility Commission that would have transferred Entergy's Gulf Coast transmission network to ITC Holdings. Administrative judges recommended that the commission reject the proposal, noting that no other states or local governments had ruled on the issue yet. ITC was also set to boost prices for energy delivery, with critics arguing there was no justifiable reason for the hike.

Fool contributor John Divine has no position in any stocks mentioned. You can follow him on Twitter @divinebizkid and on Motley Fool CAPS @TMFDivine.

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