Despite a rather defensive sector, these firms have been out of control. Their shares have appreciated by tens to hundreds of percent and investors may pay the price today. Valuations of many big titles have reached levels that hardly match the pace of earnings growth anymore. This greatly increases the risk that even a minor earnings disappointment or bad news could trigger a severe correction. And for the following companies, according to the Fair Price Index, the correction could be more than substantial. So if you're considering them or have them in your portfolio, you should pay attention.

The health care sector has long been viewed as one of the most stable pillars of the stock market. Indeed, an aging population, rising health care spending and technological advances have combined to create an environment that allows companies to generate relatively predictable earnings even during economic slowdowns. But it also potentially makes this sector the sector of the future (but more on…