The average investor has more than 5,000 publicly traded stocks on reputable U.S. exchanges to choose from. With that many stalks of hay in the barn, finding that proverbial needle in the haystack can be quite difficult.

If you're looking for perhaps the world's most perfect stock, your search might end with the original biotech blue-chip stock, Amgen (AMGN -2.75%). On a split-adjusted basis, Amgen shares have increased in value by nearly 156,000% since September 1984, and there are plenty of reasons to believe the company isn't anywhere near done yet.

Here are 10 reasons Amgen just might be the world's most perfect stock.

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1. Little change at the top

Warren Buffett has often opined that great businesses can run themselves, regardless of whether you have a good management team in place or not. But, I'd add that having a consistent message and strategy definitely helps. Since its founding in 1980, Amgen has had just four CEOs, with its latest, Bob Bradway, holding the job since 2012.

It's also been 15 years since Amgen produced an annual loss (which was based on a one-time acquisition write-off rather than an operating loss). In short, this is a company with a clear vision and a history of generating profits.

2. Label expansion opportunities

While we could easily crow all day about Amgen's existing product portfolio, it's the company's label expansion opportunities that could really drive its growth. The possibility for oncology drug Kyprolis, or LDL-cholesterol-lowering injection Repatha, to garner new indications could propel these therapies to years of double-digit growth rates.

Repatha is of particular interest since both the phase 3 clinical studies and long-term cardiovascular outcomes studies showed a clear benefit to patients using the drug. If Amgen and insurers can meet in the middle on pricing, it could easily have a blockbuster drug on its hands.

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3. Healthy pipeline

However, having an impressive and diversified product portfolio is only half the challenge. Because patents on branded therapies eventually expire, it's important to have an expansive clinical-stage pipeline -- and Amgen has just that.

Since 2014, the company has brought around a half-dozen novel therapies to market, and it currently has more than 30 ongoing clinical trials. Many of its pivotal phase 3 trials are for label expansion purposes, but there are a host of novel therapies in phase 1 and 2 of development as we speak. In other words, Amgen has the opportunity to replace the revenue it'll lose from branded therapies as they come off patent.

4. Biosimilars

Amgen is also at the forefront of a new trend in the drugmaking industry: biosimilars. A biosimilar drug is a copycat version of a biologic drug, and it's designed to be roughly as effective as a brand-name product, but for a cheaper price. Since biosimilar drugs are so new, the expectation is they'll price at a 10% to 50% discount to branded therapies.

Amgen is currently developing seven biosimilars that are designed to go after major blockbuster drugs, including Rituxan, Avastin, and the best-selling drug in the world, Humira, to name a few. It's unclear what legal obstacles Amgen might run into when trying to launch these biosimilars (assuming they're effective), but Amgen is, in a way, hedging its bet on the future of medicine with this new channel of revenue.

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5. Acquisitions

Over the past three years, Amgen has generated over $25 billion in aggregate free cash flow, which gives the company a number of options in how it can reinvest in its business. One path the company will utilize from time to time is inorganic growth (i.e., acquisitions).

For example, in May 2009, Amgen announced that it would be acquiring Immunex for $16 billion, which allowed Amgen to bring Enbrel into its portfolio. Enbrel has grown to become Amgen's top-selling product, with sales growing 11% in 2016 to $6 billion. There are no guarantees that Amgen's acquisitions will be winners, but the sheer fact that it has the flexibility to go shopping is a positive for long-term investors.

6. Pricing power

Another factor that's long worked in Amgen's favor (and in the favor of most drug developers) is the company's excellent pricing power. Last year, Enbrel's 11% sales growth was entirely derived from price increases that it was able to pass along to insurers.

There are a plethora of factors that make selling prescription drugs in the U.S. favorable for drugmakers. The U.S. has the highest demand for pharmaceutical products of any country in the world, and we have no universal healthcare system. Additionally, insurers won't question pricing too often for fear of alienating their own members. And, of course, we can't forget the exceptionally long patent periods (often 20 years) attached to developing drugs.

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7. Cost controls

Despite its robust pipeline, affinity for collaborations, and its occasional acquisition, Amgen has also shown Wall Street that it knows how to trim the fat when needed. In 2014, Amgen wound up laying off 4,000 employees, or 20% of its workforce, in order to save $1.5 billion annually. The move wasn't made simply to boost its operating margins (although it has indeed done just that). Amgen reduced its headcount in order to funnel some of its savings over to multiple phase 3 trials and expected drug launches. It's this on-the-feet thinking by management that has Amgen running so efficiently.

8. International expansion opportunity

An oft-overlooked fact of biotech darling Amgen is that it's heavily reliant on the U.S. for a good portion of its sales. As noted earlier, with pricing power being superior in the U.S., this isn't necessarily a bad problem to have. However, Amgen's lack of presence in Europe and other foreign countries gives it a potential path to new revenue.

According to the company's full-year report from 2016, just $4.57 billion of its $21.89 billion in total product sales was derived from the rest of world markets. Amgen has a real shot to grow Kyprolis, Aranesp, Enbrel, and Vectibix in foreign markets in the years to come and help add a bit more geographic balance to its sales profile.

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9. Shareholder yield

When it comes to dividends among biotech stocks, Amgen is the one of the premier names. It began paying its shareholders a dividend back in 2011, and it has since grown its stipend annually. Over the past six years, its payout has increased by an amazing 311%, with the company currently yielding an S&P 500-topping 2.8%.

On top of its generous dividend, Amgen has regularly been buying back its own stock for a long time. Stock buybacks reduce the number of shares outstanding and can help increase EPS, which in turn may help push a company's share price higher. Since 2007, Amgen has reduced its outstanding share count by about 370 million. 

10. Valuation

Last, but certainly not least, even after its nearly 156,000% romp higher since September 1984, Amgen is still attractively priced. The company's forward P/E of 12.8 is notably lower than that of the S&P 500. More importantly, it's significantly lower than the average P/E Amgen has traded at over the past five years of 18.6. If Amgen can continue to grow its portfolio and pipeline organically and inorganically, then there's a pretty decent chance, in my view, that this potentially perfect stock could head higher over the long run.