Many investors find it hard to get in on the stock market given how volatile it has been all year, and the fact that some economists are predicting that a recession is coming soon doesn't make things better. With that said, there are businesses worth investing in even in these troubled times.

Those companies with robust businesses and exciting opportunities will still perform well in the long run even if they don't make it through the market's near-term issues entirely unscathed. Let's look at two such companies: Pfizer (PFE 0.12%) and HCA Healthcare (HCA -0.09%). Here's why both of these monster stocks deserve a place in your portfolio.

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1. Pfizer 

Pfizer is one of the companies behind the leading coronavirus vaccine known as Comirnaty. The pharma giant developed it in collaboration with BioNTech. The fantastic commercial success that Comirnaty has had will help Pfizer lay a solid foundation for the future. Last year, the coronavirus vaccine generated $36.8 billion in revenue for the company.

That's almost as much as the $41.7 billion in total revenue the drugmaker reported in 2020. Pfizer's total revenue in 2021 soared by 92% year over year to $81.3 billion. The company's adjusted net income almost doubled to $25.2 billion. Pfizer ended 2021 with free cash flow of $29.9 billion, a 41.3% year-over-year increase.

Physician vaccinating a child.

Image source: Getty Images.

With its massive pile of cash, Pfizer has the means to throw money at competing pharmaceutical companies to acquire promising clinical compounds. The pharma giant recently closed its $6.7 billion acquisition (in cash) of Arena Pharmaceuticals, a clinical-stage biopharmaceutical company that focuses on developing treatments for immuno-inflammatory diseases.

Perhaps the key asset Pfizer got its hands on through this acquisition is etrasimod, a potential treatment for ulcerative colitis that is showing real promise. The drugmaker does have other exciting products in its lineup, including immunosuppressant Xeljanz, anticoagulant Eliquis, and cancer medicines Xtandy and Inlyta. The company's biosimilar business has been performing well, too.

Like other drugmakers, Pfizer benefits from patent protection for the novel therapies it develops. That grants the company some degree of pricing power for the length of the patent. And thanks to a rich pipeline, the healthcare giant has the means to replenish its lineup to smooth out the declining sales of older products that have lost patent exclusivity.

In the future, Pfizer will continue to thrive for one simple reason: lifesaving medicines are always in demand. No one gets to choose when life-threatening illnesses strike, and even amid the worst economic recessions, the need for drugs remains relatively high. What's more, due to an aging world population, drugmakers will become even more invaluable in the coming years.

As a leading player in the pharmaceutical industry, Pfizer is well-positioned to benefit from this long-term trend. Those who get in on this monster stock today will be handsomely rewarded. 

2. HCA Healthcare

HCA Healthcare will benefit from some of the same long-term trends that boost Pfizer. An older population will require more medical services, including those that HCA Healthcare provides as a hospital chain operator. What sets HCA Healthcare apart from its peers is the breadth of its operations throughout the U.S.

It is one of the largest hospital chains in the country with a total of 182 facilities under its name as of the end of 2021. This includes acute care hospitals, psychiatric hospitals, surgery centers, and more. The company's strategy for the future is, among other things, to add to its already rich portfolio of facilities. That can help HCA Healthcare attract more and more patients and third-party payers onto its network, thereby increasing its competitive position.

HCA Healthcare held a 23% market share in 2011, which grew to 27% at the end of 2020. The company's latest numbers indicate that it also gained market share during the pandemic, going from 26.5% as of the end of 2019 to just under 28% at the end of 2021.

Clearly, HCA Healthcare is doing something right. And with HCA's already established network and the funds to continue investing in its future, investors can count on the company to make more headway into this competitive market. Last year, HCA Healthcare managed to report solid results despite the continued impact of the pandemic.

2021 revenue totaled $58.8 billion, 14% higher than the previous year while adjusted earnings per share came in at $17.50 compared to the $11.61 in 2020. There are many more years of robust financial results ahead for this healthcare company. That's why it's worth looking beyond the market's recent troubles and buying HCA Healthcare shares today.