AstraZeneca (NASDAQ:AZN) ranks as one of the top big drugmakers in terms of stock performance so far this year. That's not surprising, considering the company's solid quarterly updates and the positive publicity that it's garnered for its coronavirus vaccine program.

But is AstraZeneca stock a buy now? My answer is a resounding "yes." Here are three key reasons why.

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1. Multiple juggernaut franchises

Some drugmakers specialize in one area where they really make their mark. AstraZeneca's success stems from not just one, but multiple juggernaut franchises. 

Sales for AstraZeneca's oncology drugs continue to soar. Lung cancer drug Tagrisso now generates close to 16% of the company's total revenue. Imfinzi and Lynparza are picking up strong momentum, as is Calquence. Overall, AstraZeneca's oncology drugs delivered year-over-year sales growth of 26% in the first half of 2020.

AstraZeneca is also a major player in cardiovascular, renal, and metabolism (CVRM) indications. Sales for diabetes drug Farxiga and blood thinner Brilinta are growing by double-digit percentages. The strength of these two blockbuster drugs is more than enough to offset sales declines for diabetes drugs Bydureon, Byetta, and Onglyza.

The company's respiratory and immunology franchise continues to deliver solid growth, as well. Respiratory drugs Symbicort and Fasenra are leading the way, with sales jumping 23% and 44%, respectively, in the first half of the year.

2. A loaded pipeline

Wall Street analysts project that AstraZeneca will grow its earnings by an average annual rate of 19% over the next five years. The company's current lineup will fuel much of this growth. But AstraZeneca also boasts a pipeline loaded with potential winners.

The company has 166 programs in its pipeline. Close to two dozen of them are in phase 3 clinical studies. Many of these late-stage programs target additional indications for already-approved drugs, including Imfinzi and Lynparza. AstraZeneca also has new late-stage drug candidates, notably including roxadustat, which targets the treatment of anemia in chronic kidney disease, and tezepelumab in treating asthma.

There's one pipeline candidate that's understandably generating a lot of interest right now: investigational COVID-19 vaccine AZD1222. AstraZeneca teamed up with the University of Oxford earlier this year to develop the vaccine candidate. AZD1222 is now one of only a handful of COVID-19 vaccine candidates in late-stage testing. The company has lined up several high-dollar supply agreements, including a $1.2 billion deal with the U.S. government to supply up to 300 million doses.

3. Don't forget the dividend

Megablockbuster franchises in oncology, CVRM, and respiratory and immunology combined with a deep and promising pipeline make this big pharma stock a good pick. But don't forget AstraZeneca's dividend yield of more than 2.5%.

How important is that dividend? Over the last 10 years, the total return of the stock has more than doubled its share-price appreciation thanks to the power of reinvested dividends.

Any reasons for concern?

All stocks face risks. AstraZeneca isn't an exception. There's always a possibility that a pipeline candidate could flop in clinical testing. Current drugs could face increased competition. Some might also worry that AstraZeneca won't make much money from AZD1222 since the company has committed to supplying the coronavirus vaccine for no profit in Europe.

However, my view is that AstraZeneca's opportunities far outweigh its risks. It's also important to note that the company could make a profit from AZD1222 once the COVID-19 pandemic is over. For investors looking for a relatively low-risk growth opportunity that offers an attractive dividend, AstraZeneca looks like a great pick.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.