Valued at more than $36 billion, the portfolio of the Bill & Melinda Gates Foundation Trust includes 22 holdings based on its most-recent filing, many of which are dividend stocks. The Gates Foundation uses the sizable passive income that the portfolio generates to help fund its prodigious philanthropic work.

Of the various stocks that return capital to shareholders, two that stand out among the trust's holdings are United Parcel Service (UPS 0.14%) and Crown Castle (CCI -0.67%), both of which are high-yield dividend stocks. Below, two fool.com contributors dig into why the foundation values these stocks highly enough to include them in its portfolio and why Main Street investors might also want to add them.

A challenging 2023, but long-term growth looks assured

Lee Samaha (UPS): It's not shaping up to be a vintage year for UPS. A weakening economy and protracted labor negotiations with the Teamsters have caused management to lower its full-year guidance twice this year. 

Having gone into the year expecting revenue of $97 billion to $99.4 billion, and an operating margin of 12.8% to 13.6%, management now expects $93 billion and 11.8%, respectively. It's disappointing, but it needs to be put into context. There's little UPS can do about its end markets, but it can resolve its negotiations with the Teamsters and continue to structure its business for long-term growth. 

The excellent news is that UPS has an agreement with the Teamsters , and it continues to work on expanding revenue in key end markets such as healthcare and small and medium-size businesses (SMBs). 

An example of the latter comes from the international expansion of its digital access program (DAP), a highly successful program offering services to enable SMBs' e-commerce activity. At the same time, UPS is willing to forgo lower-margin deliveries. Indeed, even though U.S. domestic package volume declined 9.9% in the second quarter, its average revenue per piece rose 3.3%.

As such, UPS will likely emerge from the volume slowdown as a stronger company. Meanwhile, its 3.6% dividend yield is attractive for income-seeking investors while they wait for UPS to see better end markets.

5G deployment will drive dividend growth  

Scott Levine (Crown Castle): It's not the largest holding in the portfolio (that honor belongs to Microsoft), but what Crown Castle stock can lay claim to is certainly significant. With a juicy 5.5% forward yield, it is the highest-yielding dividend stock in the Gates Foundation's portfolio.

And fortunately for income investors, shares are attractively priced at 13.9 times operating cash flow, a discount to their five-year average cash-flow multiple of 23.3.

As a real estate investment trust (REIT), Crown Castle might not be a household name, but it's a company that Americans unknowingly rely on tremendously. With an expansive presence throughout the United States, it helps facilitate wireless communications with its portfolio of 40,000 cell towers, 120,000 small-cell nodes (which help to strengthen network capacity in areas of high demand), and about 85,000 route miles of fiber cables.

The REIT's dividend is already substantial, and the company forecasts growing it further for years to come, targeting a long-term annual growth rate of 7% to 8%. Management reiterated on the company's recent second-quarter 2023 conference call that it bases this outlook on consistent growth in tower organic revenue of 5% following the initial rollout of 5G.

And Crown Castle has 60,000 small cells in its backlog. As these are deployed over the next few years, the company expects to generate double-digit small-cell revenue growth beginning in 2024.

Are these Gates Foundation stocks right for you?

In light of the ample dividend income that UPS and Crown Castle provide, it's no wonder the Gates Foundation includes them among its holdings.

Those on Main Street who are also delighted with the prospect of UPS delivering dividend income should find the company's clarity with its labor relations encouraging as well as its future growth prospects.

Similarly, those looking for a higher-yielding dividend or those interested in gaining some REIT exposure linked to wireless communications would be well served to scoop up shares of Crown Castle.