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.

Utilities and telecom stocks were some of the day's big winners, as nine out of 10 market sectors edged higher Friday. While earnings reports from big-name companies drove the S&P 500 Index (SNPINDEX:^GSPC) to all-time highs today, earnings were also the catalyst responsible for the day's biggest losers. With durable goods orders rising more than expected in September, the S&P 500 added 7 points, or 0.4%, to end at a record close of 1,759. 

Health-care company Express Scripts (NASDAQ:ESRX) was one of the benchmark's steepest decliners, slumping 4.5% Friday as the market reacted to its third-quarter results. Trading at nearly 30 times earnings, investors expected a bit more than 9% year-over-year earnings growth. Adding insult to injury, Express Scripts' sales fell in the most recent quarter and lowered its full-year forecasts as the number of prescriptions it processed fell. If more clients decide to go the way of UnitedHealth Group (NYSE: UNH), which stopped outsourcing pharmacy benefits management this year, the stock could face more downbeat days like this in the future. 

Shares in application software company F5 Networks (NASDAQ:FFIV), which manages network traffic for service providers and other business customers across the globe, shed 2.9%. The stock trended lower as investors continued to react to its earnings report on Wednesday, which, as my colleague Tim Beyers noted yesterday, highlighted a troubling trend. Margins are expected to slip in the next year, as the company derives an increasing amount of business from its less lucrative consulting business, which now accounts for most of the company's sales growth. 

Lastly, stock in health-care information technology giant Cerner (NASDAQ:CERN) posted 2.8% losses. If you hear "health-care information technology" and think "Obamacare," you're on to something. Cerner has benefited enormously from the Affordable Care Act already since its technology enables health-care providers to communicate more effectively. But Obamacare is off to a poor start, as early problems with its website draw heavy criticism from political opponents of the program. That, however, had little to do with today's sell-off, which was instigated by disappointing third-quarter revenue from its tech resale business. 

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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