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It's easier said than done, but one of the best ways to ensure above average returns is to buy great companies at great prices and hold on for a long time. Maybe you've honed a value investing strategy over the years or are looking to start in 2017. Either way, here's why Gilead Sciences (GILD 3.27%), Akorn (AKRX), and Amgen (AMGN 0.71%) are three bargain stocks to put on your radar.

What goes up...

Gilead Sciences rode good fortunes with its innovative Hepatitis C drug portfolio to amazing gains in recent years. The company's cures helped it generate an unheard of $30 billion in net income in 2014 and 2015. The stock price rose accordingly, peaking at $120 per share in mid-2015, but has slowly cooled off in the time since, giving back 40% of the gains. It's down 22% in the last year alone.  

GILD Chart

GILD data by YCharts

You could argue that investors are playing it safe. After all, sales will decline in future periods as increasing competition forces drug prices to drop and the pool of available patients to dwindle. You could also argue that things are getting a little out of hand. Gilead Sciences now trades at a trailing P/E ratio of 6.7 -- well below peers in the $100 billion market cap neighborhood. The company is far from broken, but investors appear to be writing it off for dead. 

Management knows it will continue to face pressure from analysts seeking a big acquisition, which is one reason it instituted a respectable quarterly dividend in early 2015. Management also knows that, despite a recent string of clinical failures, it doesn't have to make any kneejerk reactions. With $12.2 billion in cash and short-term investments, quarterly revenues topping $7 billion, and healthy profits rolling in, long-term investors may want to give Gilead Sciences a closer look.

A forgotten, unconventional pharma stock

A tumultuous year for Akorn has done little to attract value investors to the stock. The specialty pharmaceutical company has been caught in the fury of a U.S. Department of Justice probe eyeing generic drug manufacturers for price collusion. At this point, it's mostly by association, but it has been enough to send the stock 26% lower in the past year. 

AKRX Chart

AKRX data by YCharts

Here's the thing: Akorn is an amazing growth stock -- with plenty of growth left -- that has rarely been cheaper. Investors would have to go all the way back to a short-lived period in late 2011 to find a comparable trailing P/E ratio for the stock.

Moreover, the company grew revenue 77% from 2014 to 2015. While year-over-year growth will drop to the mid-teens for 2016, Akorn expects to gain another 12 product approvals in the first quarter of 2017 with at least another 10 approvals later in the year. The strategy isn't to own the next big blockbuster, but rather to have an extraordinary number of shots on goal that collectively add up to a giant opportunity. It hasn't failed investors so far, and a strong pipeline of products with over $4.3 billion in estimated revenue potential three years out and $8.7 billion in all supports putting this pharma opportunist on your radar.

Amgen is historically cheap

While most blue chip pharma stocks trade at trailing P/E ratios of at least 30, Wall Street has pegged Amgen to a P/E ratio of just 15.5 -- a level only ever seen during a brief two-year period that ended in 2011. Why is it so cheap now? 

Investors appear to be worried about stagnant revenue growth and fierce competition to some of the company's best-selling drugs. Enbrel is one of the pioneering biologic drugs most at risk of generic competition, with at least one biosimilar already approved. Amgen's industry-leading blood disorder portfolio faces similar challenges from newcomers. Meanwhile, the biopharma's most promising growth product, cholesterol drug Repatha, recently won a long-standing legal dispute with Sanofi and Regeneron. The mixed bag of news has the stock up just 2.3% in the last year. 

AMGN Chart

AMGN data by YCharts

The ho-hum performance looks worse than it is, in my opinion. There's plenty to like about Amgen's future growth potential, even if it's forced to move on from several drugs that have played an instrumental role in the last decade. It ended September with $38 billion in cash, has been repurchasing millions of shares of stock in recent quarters, and will increase its dividend 15% in 2017. The biopharma pioneer has a healthy pipeline of product candidates including nine biosimilars, which could generate hundreds of millions in annual revenue if approved. And while analysts previously expected peak annual sales of Repatha to hit $5 billion, squashing Sanofi and Regeneron in court could push that figure to $7 billion.

If the worst case scenario is overblown, then Amgen looks like a steal.

What does it mean for investors?

It's a little ironic that new companies have to work so hard to prove themselves to investors, who can grow complacent with years of good fortune and then run for the exits at the first sign of trouble. Ironic or not, that leaves these three solid companies trading at great prices for value investors looking to scoop up bargain stocks.