Worldwide pharmaceutical sales were roughly $1 trillion in 2016, according to Statista. That's a massive number that should grow over time as the global population continues to age.

Given the market size and natural tailwind, it shouldn't be surprising that many pharma companies have grown to become truly gigantic. For proof, here's a look at the market cap of 10 of the largest publicly traded pharmaceutical companies in the world:

Company Market Cap
Johnson & Johnson (NYSE:JNJ) $376 billion
Novartis AG  $235 billion
Pfizer $219 billion
AbbVie (NYSE:ABBV) $185 billion
Merck & Co.  $163 billion
Sanofi  $110 billion
Bristol-Myers Squibb (NYSE:BMY) $104 billion
GlaxoSmithKline $93 billion
Eli Lilly and Company $91 billion
AstraZeneca  $91 billion

Data source: Finviz.com.

So which of these big-pharma stocks should investors favor today? Here's why Johnson & Johnson, AbbVie, and Bristol-Myers Squibb are my three favorites.

Colorful drugs on top of hundred dollar bills

Image source: Getty Images.

Johnson & Johnson

While Johnson & Johnson might not be a "pure play" pharmaceutical stock -- slightly more than half of this company's revenue comes from medical device and consumer products sales -- there's no doubt that J&J's future will be powered by its pharmaceutical division. Last year J&J's pharma sales grew by 17%, which is far faster than the 8% and 3% growth rates posted by its medical device and consumer products segments, respectively.

What's behind the big jump in J&J's pharma sales? Investors can largely attribute the gains to the continued success of next-generation drugs. This includes the autoimmune-disease drug Stelara, the anticoagulant Xarelto, and the cancer drugs Imbruvica, Zytiga, and Darzalex. Growth in these top-selling medicines is more than offsetting the declines in J&J's top-selling drug Remicade, which is a legacy cancer drug facing increased competition from biosimilars.

J&J's plan to keep pharma sales heading in the right direction is straightforward. The company boasts a number of trials in place that promise to expand the labeling for many of the fast-growing drugs listed above. The recent acquisition of Actelion also added a few potential blockbusters to the company's lineup and should provide needle-moving revenue. Meanwhile, J&J's vast pipeline and broad list of partnerships promise to introduce new blockbuster drugs to its portfolio.

In total, J&J boasts a strong product lineup that is poised to grow rapidly over time. Combining this with the company's knack for making tuck-in acquisitions, improving margins, and buying back stock, Wall Street projects that overall profit growth will exceed 7% annually over the long term. That's not too shabby for an established industry giant that offers up a well-covered dividend yield of more than 2%.

Doctor and patient looking at a piece of paper and smiling

Image source: Getty Images.

AbbVie

AbbVie's long-term success is attributable to a single name: Humira. This anti-inflammatory drug has powered the company's top- and bottom-line growth for years and is currently ranked as the best-selling drug in the world. In 2017 Humira hauled in about $18 billion in total sales and accounted for more than 60% of AbbVie's revenue. As amazing as that number is, Humira is still poised to post substantial growth over the coming years.

There is a downside to having such a dominant drug, though: What happens to AbbVie when Humira finally loses patent protection?

AbbVie's management team has been pondering that question for years. Thankfully, CEO Rick Gonzalez recently shared his company's long-term growth plan with investors at the J.P. Morgan Healthcare Conference.

So what is the plan? First, the company will wheel and deal to ensure that Humira pumps out revenue for as long as possible. Next, AbbVie plans to emphasize growth in its other top-selling drugs -- namely the cancer drug Imbruvica and the hepatitis C drug Mavyret -- as much as possible. Finally, the company boasts a number of pipeline drugs that hold great promise. This includes a lung cancer drug called Rova-T and an endometriosis drug called elagolix, both of which could turn into blockbusters.

Gonzalez predicted that, all told, AbbVie's non-Humira sales will eclipse $35 billion by 2025. For context, AbbVie's non-Humira sales in 2017 were about $13 billion. If achieved, that number should be big enough to offset the eventual Humira decline.

Beyond revenue growth, management also sees ample room for profit enhancement through margin expansion. The company's operating margin is "only" about 38% right now. Management believes it can ultimately bring that number up to 50% by 2020.

When added together, Wall Street believes that this one-two punch will drive 16% annualized profit growth over the next five years. That makes AbbVie one of the fastest-growing big-pharma companies in the world.

Turning to the dividend, AbbVie currently offers up a yield of 2.4% and boasts a long history of passing along increases to shareholders. With profits set to rise, I think investors can expect more of the same.

An assortment of colorful medications on top of $100 bills

Image source: Getty Images.

Bristol-Myers Squibb

Like many of its big-pharma brethren, Bristol-Myers Squibb recently muddled through a difficult period when it saw several top-selling drugs lose patent protection. Thankfully, the massive success of two recently launched megablockbuster drugs is more than offsetting those losses.

The first drug driving the turnaround is a blood thinner called Eliquis (which is being commercialized with the help of Pfizer). Eliquis is a best-of-breed anticoagulant that is wresting market share away from the legacy drug warfarin. It is also more than holding its own against J&J's next-generation drug Xarelto. Total Eliquis sales should come in around $5 billion for 2017, and still look to have plenty of room to run.

BMS's other wonder drug is Opdivo, an approved treatment for 11 different types of cancer. Opdivo is also flying off the shelves and, like Eliquis, should pull in nearly $5 billion in total sales in 2017. That's exciting, but management believes that Opdivo also holds promise to treat lung, renal-cell, gastric, and liver cancer. Each of these potential label-expansion claims could add another $1 billion to the drug's peak sales potential.

While Eliquis and Opdivo are clearly the stars of the show, BMS also owns a number of other fast-growing drugs that are driving financial gains. These include the rheumatoid arthritis drug Orencia and the cancer drugs Sprycel, Yervoy, and Empliciti. Combined, these drugs contribute another $5 billion or so to the company's top line, and are growing by double digits.

All told, market-watchers expect that these drugs will power earnings growth of more than 10% annually over the next five years. BMS's dividend yield of 2.5% looks like icing on the cake.

The Foolish bottom line

The aging of the baby-boomer generation should drive steady demand for prescription drugs in the years ahead. That's a great tailwind for drugmakers in general, but the three companies discussed above look particularly well-positioned to profit.

If you're a healthcare investor who likes to buy and hold great companies, I think all three of these big-pharma giants are excellent choices.

Brian Feroldi has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Johnson & Johnson. The Motley Fool has a disclosure policy.