The top wealth-creating stocks have put $21 trillion back into shareholders' pockets — and 3 are still cheap to buy

• Big Tech firms like Nvidia, Apple, and Microsoft lead in shareholder value creation.

• Stocks with a wide economic moat can be a good long-term investment.

• But only Microsoft, Alphabet, and UnitedHealth Group are rated undervalued by Morningstar.

Past performance does not guarantee future success; it's a line frequently used for investing advice. That's because stocks are a moving target amid shifting fundamentals, business cycles, interest rates, and inflation.

But that doesn't mean their historical strength can't be considered. If a company's stock has continued to rise, especially for over a decade, that sustained performance suggests it's doing something right. And it could be a good starting point to filter for good long-term investments or see if any common characteristics helped them succeed.

Amy Arnott, a portfolio strategist at Morningstar, recently did just that by pulling a list of the top stocks that have created the most value for investors over the past decade. One common denominator among the vast majority of them is that they have wide economic moats, which means they are less likely to face competition in the next 20 years. This is especially important for companies spending mega dollars — like AI players — in hopes of reaping long-term benefits and wider market share. And to do that, they need a long runway with little competion to reap the returns of their capital expenditure for many years.

She also found that stocks able to create a lot of value over long periods of time tend to continue performing well for many years, which reinforces the approach of Warren Buffett, who once quipped that the ideal holding period is forever.

In this instance, Arnott measured value creation by looking at the biggest increases in market cap from 2015 through 2024, plus the value of dividends each company paid.

The list she pulled includes 15 sector-neutral names. Unsurprisingly, Big Tech, and more specifically Nvidia, tops the list as the stock that has returned the most value to shareholders, with more than $3 trillion in value created. It is followed by Apple, Microsoft, Amazon, Alphabet, Meta, Tesla, and Broadcom, all of which created more than $1 trillion in shareholder value.

However, even if these names are well recognized, it doesn't mean it's a good time to buy shares. While there's a mixed bag of reasons a stock can fall out of favor, one of the central ones is simply that the share price already reflects the strength of the company.

Nonetheless, three names stand out for being rated four stars out of five, which means Morningstar considers them moderately undervalued or trading at slight discounts to their analysts' fair-value estimates.