The S&P 500 Index (SNPINDEX:^GSPC) ended the day and the week on a higher note, logging its third straight week of gains, as the bull market in equities continues. The index added seven points, or 0.4%, to end at 1,633. Still, a few S&P companies managed to disappoint the market, and their shortcomings were reflected in their outsized losses today. 

Just a few days after Cognizant Technology Solutions (NASDAQ:CTSH) reported earnings that sent shares in the IT and consulting company up 5%, the stock slipped 5%. To be fair to Cognizant, the stumble may be more due to political happenings than anything it's done wrong. An immigration reform bill in the Senate, considered a potential boon to the technology sector, is very unlikely to make it through the House of Representatives. As Cognizant President Gordon Coburn remarked in the earnings call, this is according to the very Senator who authored the bill.

Oil refiner Tesoro (NYSE:ANDV) lost 2.9% today, on a day when the oil and gas sector, as a whole, was the worst performing of the 10 major sectors. Tesoro is reeling from a recent shutdown in a Washington state refinery earlier this week after a leak was discovered. Thankfully, the issue has been resolved, but the 125,000-barrel-per-day refinery lost some meaningful business in the process.

Lastly, and quite fittingly considering the weak showing in energy today, another oil refiner rounds out our list of underperformers. Hess (NYSE:HES) shares slipped 2.3% after the company bowed to Elliott Management, a hedge fund that had demanded change at the upper levels of the company. Hess will split the roles of CEO and chairman -- positions that are currently occupied by one man, John Hess -- after the annual meeting next week.