If you want to beat the market, the key is having strong stocks in your portfolio of businesses that are profitable and growing. One name that has routinely outperformed the markets is health insurance giant UnitedHealth Group (UNH 0.06%). While it may not be a hot tech stock and health insurance may not sound all that exciting, the stock's returns can be.

UnitedHealth is one of the top healthcare companies, and here's a look at why it can help you beat the Dow Jones Industrial Average.

A solid business with strong fundamentals

Health insurance is a necessity for millions of Americans. And while people may cut their cable bill or spending on home improvement and other discretionary expenses, healthcare is a necessity. It makes a company such as UnitedHealth relatively resilient in tough times.

This year, the healthcare stock's returns have been flat. But it has been rallying in the past month as the company has reminded investors why it's a fantastic investment. On Oct. 13, UnitedHealth posted its latest results. Through the first nine months of the year, the company's revenue totaled $277.2 billion, rising 15% year over year. Net earnings of $17.5 billion are also up 11%, even as healthcare costs have been rising.

Although UnitedHealth doesn't post huge margins, they have been growing over the years.

UNH Profit Margin Chart

UNH Profit Margin data by YCharts

The healthcare giant also keeps growing

What's also encouraging for long-term investors is that the business is constantly on the hunt for ways to do better and provide more value. One thing investors may be surprised to learn is that for years now, UnitedHealth has been turning to artificial intelligence even before all the cool tech stocks were constantly talking about it. The company uses chips from Nvidia to develop deep learning models that help it more efficiently approve insurance claims, which could otherwise be a huge bottleneck for the business.

UnitedHealth has also been looking outwardly to expand its operations. In February, it closed on its $5.4 billion acquisition of home health company LHC Group. A year ago, it closed on a transaction to acquire data analytics company Change Healthcare, which cost UnitedHealth close to $8 billion.

Those types of acquisitions serve to improve the company's efficiency and extend its reach into new opportunities, such as home health. It's that pursuit of constant growth that makes UnitedHealth a stock worth owning for the long haul.

It's outperformed -- and that should continue

Over the years, UnitedHealth has soundly beaten the markets and been a top stock. If you owned shares of the healthcare company five years ago, your investment would be worth close to double what it was back then. By comparison, the Dow Jones Industrial Average has only risen by about 32% over that same stretch.

The past doesn't predict the future but given UnitedHealth's strong financials and continued growth, it's likely to continue to outperform the market. And at only 23 times its profits, the stock is cheap -- the average stock in the Health Care Selector SPDR Fund trades at a multiple of more than 25. 

An ideal stock for long-term investors

If you're a long-term investor, UnitedHealth is a stock you should consider holding on to for not just years but even decades. The business is in great shape and the stock also pays a dividend, which yields around 1.4%. It looks poised to continue beating the markets.