Nasdaq Biotechnology Index Climbing Since 2009

 | Jun 17, 2015 07:22AM ET

Over the past five years, one sector has outperformed all others in the S&P 500: healthcare.

Biotech stocks have led the way, with the Nasdaq Biotechnology Index climbing a whopping 520% since early 2009.

The sector’s incredible run hasn’t dampened enthusiasm for the future, either. Healthcare stocks continue to receive bullish outlooks, and some are even taking on an air of invincibility.

In early 2015, InvestorPlace dubbed more than half a dozen healthcare stocks “immune” to market declines. And Mario Minotti of Minotti Group Wealth Advisors recently told TheStreet.com that he still sees “a lot of growth potential” in biotech right now.

The problem, of course, is that this seemingly unstoppable trend can’t last forever. Indeed, a number of healthcare stocks have become extremely overvalued, and eventually they’re going to correct. Don’t be left holding the bag when they do…

h2 Far From Invincible/h2

This warning is particularly salient for income investors, as healthcare stocks often pay solid dividends and may seem like attractive investments. Yet without doing the proper research, income seekers could end up with serious buyer’s remorse.

To avoid falling for supposedly invincible yet overvalued companies, we need to look at valuation metrics. Comparing a company’s valuation to the market or to its industry is fine, but it’s also important to compare the company’s current valuation to its 10-year averages. Let’s look at Merck & Co. (NYSE:MRK) as an example.

Merck is one of the world’s largest developers, manufactures, and distributors of pharmaceuticals. Its product categories include heart and respiratory health, infectious diseases, and women’s health. At the moment, many of its biggest products are used to fight cancer.

Merck currently yields 3.1%, which is nothing to sneeze at. Of course, five-year dividend growth of 18% isn’t good, but management has bumped the payout every year since 2011.

However, problems arise when we start looking at Merck’s valuation: