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 delivered great news for many stock investors, as major market averages closed the week with gains of more than 1% to wipe out the losses from Monday's market plunge. Yet, even though most stocks benefited from today's optimism, LinkedIn (LNKD.DL), NCR (VYX 0.90%), and Cigna (CI) weren't so lucky, with sharp declines even on a positive day.

LinkedIn (LNKD) fell 6% despite posting impressive revenue growth during its most recent quarter. Sales rose 47%, but the business social-media giant said that its growth rate would slow to an estimated 33% during the current year, leading some to believe that LinkedIn's share price is too high for revenue to decelerate at such a rapid pace. Yet, the big question for LinkedIn is whether its anticipated rise in spending will pay off in long-term growth, or prove to be a wasted investment. If the net result of LinkedIn's efforts is to shift income into 2015, then today's losses could provide a smart time to buy into the company's long-term growth story.

NCR tumbled 8% after issuing a mixed earnings report last night. The company said that operating income adjusted for pension effects rose 22% from the year-ago period, but revenue increases of just 2% fell short of what investors had wanted to see. NCR's retail and hospitality segments performed especially well, but some unfavorable trends in its financial-services division held the company back. Meanwhile, NCR's future guidance was also a mixed bag, with revenue guidance looking solid, but adjusted earnings expected to come in below investors' expectations. The results show that NCR has more work to do to evolve into a full-service enterprise-solutions specialist.

Cigna (CI) dropped 9% after the health-insurance company also failed to meet earnings expectations. At the same time that costs of its private Medicare insurance business rose, Cigna expects reimbursement rates for its Medicare Advantage plans to fall in the coming year, leading it to issue earnings guidance for 2014 that were 2% to 7% below what investors had expected to see. With Cigna only projecting 1% to 2% growth in customer counts in 2014, it's apparent that the Affordable Care Act and other initiatives haven't delivered the rise in popularity in insurance that some shareholders had expected to see.