There are excellent reasons to consider investing in dividend-paying stocks. First, some investors might be looking for a source of passive income, which is something dividends can provide. Second, dividend stocks have historically outperformed their peers that do not pay dividends.

Of course, that doesn't mean that just any company which pays dividends is a great investment. But many are. Two companies that would be great additions to your dividend portfolio are pharma giants Bristol Myers Squibb (BMY -0.90%) and Amgen (AMGN 1.06%). Let's take a closer look.

1. Bristol Myers Squibb

It's imperative for dividend-seeking investors to check the health of a business. And on that front, Bristol Myers is commendable. The company continues to post solid financial results thanks to its rich lineup of drugs. In the third quarter ended Sept. 30, the company's top line grew by 10% year over year to $11.6 billion.

Patient taking a pill.

Image source: Getty Images.

For a drugmaker the size of Bristol Myers, revenue growth in the low double-digit percent range is very good. The company had products such as cancer drugs Revlimid and Opdivo and anticoagulant Eliquis to thank for this performance. Sales of Revlimid grew by 11% year over year to $3.3 billion while Opdivo's revenue of $1.9 billion jumped 7% over the year-ago period.

Opdivo went through a period of decreasing sales due to intense competition from other drugs, but it was able to turn things around thanks to a label expansion. Meanwhile, sales of Eliquis came in at $2.4 billion, 15% higher than the prior-year quarter. These three are Bristol Myers' best-selling products, but it has many others that are also helping drive top-line growth.

As of the first nine months of this year, seven of the pharma giant's medicines have already reached blockbuster status for the year, and six of the seven saw their sales increase year over year in this period. Further, the company has a full pipeline with more than 50 clinical compounds in development. New approvals and label expansions will help the company bolster its already strong lineup.

Bristol Myers currently has a dividend yield of 3.32% -- compared to the S&P 500's 1.29% -- and it boasts a very healthy cash payout ratio of 29%, giving the company ample space to raise its dividends. As a bonus, Bristol Myers looks pretty cheap, with a forward price-to-earnings (P/E) ratio of 7.9, compared to the industry's average of 13.9.

The only thing better than a solid dividend stock is a cheap dividend stock, and Bristol Myers fits the bill. Income-seeking investors can't go wrong with this pharma stock

Letter blocks spelling "dividends."

Image source: Getty Images.

2. Amgen

Biotech giant Amgen is facing a frustrating time as some of its products see a sales drop. During the third quarter, revenue from rheumatoid arthritis medicine Enbrel decreased by 3% year over year to $1.3 billion. The company blamed a decline in sales volume and a drop in net selling prices. Meanwhile, sales of Neulasta, a medicine that helps prevent neutropenia, dropped by 25% year over year to $415 million, mainly due to competition from biosimilars.

For the quarter, Amgen's total revenue increased by a modest 4% to $6.7 billion. One of the company's top performers was psoriasis arthritis treatment Otezla. During the third quarter, this medicine's sales jumped 13% year over year to $609 million.

Amgen does have other key growth drivers beyond Otezla. First, there is Lumakras, a treatment for advanced or metastatic non-small cell lung cancer (NSCLC) that earned regulatory approval in May. Lumakras targets an NSCLC mutation found in roughly 13% of this patient population, and it is the first and only cancer treatment approved by the U.S. Food and Drug Administration (FDA) in this niche market. During the third quarter (its first full quarter on the market), sales of Lumakras totaled $36 million. Investors should expect this number to rise steadily in the coming quarters, especially if it is approved abroad, as Amgen hopes.

Then there is tezepelumab, a potential treatment for severe asthma. Amgen and its partner on this program, AstraZeneca, submitted a Biologics License Application (BLA) to the FDA for tezepelumab in May. The agency granted it priority review, and Amgen expects an answer from regulators by the first quarter of 2022. The company has big hopes for tezepelumab. To quote Amgen's CEO, Robert Bradway:

[W]e're very excited about tezepelumab, a first-in-class treatment for severe asthma that we hope to launch in the U.S. next year. Given the millions of patients for whom existing asthma therapies are inadequate, we believe tezepelumab will be a significant growth driver for us for years to come.

Amgen, of course, has many other pipeline programs, including nearly two dozen in phase 3 studies.

The company's financial results will be just fine in the long run. In the meantime, its 3.43% dividend yield compares favorably to that of the S&P 500 and its cash payout ratio of 50% is reasonable. And with a forward P/E of about 12, it looks like a dividend-paying stock worth buying.