A surprise jump in the Producer Price Index, and a combined decline in consumer sentiment, sent the S&P 500 Index (SNPINDEX:^GSPC) down Friday, as stocks ended lower for the week, as well. Ending at depressed levels for the third time in four weeks, the index fell 9 points, or 0.6%, to end at 1,626. But it wasn't dim macroeconomic data that drove down shares in three of today's worst-performing S&P stocks -- all of them had their own disappointments to deal with.

Leading off the list is a familiar name: Cliffs Natural Resources (NYSE:CLF), which mines for coal, iron ore, and other resources. The company saw shares slump 5.1% today after it held up the environmental assessment of a chromite project in Ontario earlier this week. Citing certain "unresolved issues," the company is delaying the launch of the operation until it ensures its compliance with Canada's laws -- probably a good call, but not great for the stock.

Shares of Monster Beverage (NASDAQ:MNST) shed 4.4% Friday, as the American Medical Association prepares to discuss the endorsement of a ban on energy drinks to children. The group of physicians has an understandably large influence on health policy in the United States, and a move to suggest an age requirement for the high-caffeine beverages that are Monster's specialty poses a serious threat to its business.

Lastly, shares of the beleaguered retailer J.C. Penney (NYSE:JCP) lost 4.2% heading into the weekend, as the business seeks to revive its private-label brands that were ushered out by Ron Johnson. Johnson, who was ushered out as CEO himself this year, didn't last a year-and-a-half at the company, as he made a series of boneheaded moves like eliminating sales, which alienated J.C. Penney's customer base. Investors are hoping former CEO Mike Ullman can turn his direct experience running the business into success again, but he's only two months into the job, and a real turnaround will take some time.

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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