Source: Wal-Mart Stores,

Women aren't as well represented in the world's richest as are men, but there are a number of very wealthy women, including Christy Walton, who holds the title of the world's richest woman thanks to inheriting a massive ownership stake in Wal-Mart Stores (NYSE:WMT), the iconic deep-discount Goliath.

The planet's richest women
Christy Walton married John Walton, the son of Wal-Mart founder Sam Walton. After John Walton died, Christy inherited stock in Wal-Mart that makes her worth a jaw-dropping $41.7 billion (yes, with a "b"), according to Forbes.

Although Wal-Mart makes up the majority of Christy Walton's wealth, the heiress has also made a great deal of money as a shareholder in solar-energy company First Solar (NASDAQ:FSLR), a company in which she owns a 27% stake thanks to a savvy investment that Walton's investment arm, True North Partners, made in 1999.

Today, JCL FSLR Holdings LLC and JTW Trust No. 1 holds Walton's interests, and Richard Chapman, a longtime Walton confidant who serves on First Solar's board, oversees them.

Right behind Walton is Liliane Bettencourt, the heiress of L'Oreal. Bettencourt's stake in the cosmetics giant is worth $40.1 billion and came as an inheritance from her father, who was L'Oreal's founder. Although Bettencourt served on L'Oreal's board for years, her grandson replaced her in 2012.

In third place is Christy Walton's sister-in-law, Alice Walton. Like her brother John, Alice inherited a big stake in Wal-Mart that has grown to be worth $39.4 billion.

Overall, these are just three of the 197 women on the planet who are worth more than $1 billion.

Following in their footsteps
These three women inherited their wealth, but that doesn't mean there aren't lessons every investor can learn from these billionaires.

For instance, all three of these women owe their wealth to possessing large equity investments in global companies with long-standing and well-known brands.

Importantly, each of these women has seen her wealth increase by embracing a long-term view that has resulted in sticking with these companies through thick and thin.

Investors should also remember that Wal-Mart and L'Oreal were once much smaller companies and that a great deal of the increase in the wealth of these billionaires is due to decades of growth for these brands.

Tying it together
Although the average person isn't likely to amass a fortune as large as these women, investing for the long term in growing brands that have mass appeal could be a recipe for achieving millionaire status, particularly when investing begins early and is done consistently over time.

By contributing a set amount at specific intervals, such as monthly, a small nest egg can grow to be quite large. For example, a person with $10,000 who invests $400 monthly in an investment yielding an average 6.5% annually would see his or her portfolio climb to nearly $1 million over a 40-year span.

A lot of Walton's annual income comes from dividends that Wal-Mart pays, and those dividends allow Walton to hold on to her shares without needing to sell them to pay her expenses. Since dividend-paying stocks tend to outperform their non-dividend-paying peers over time, dividend-paying companies such as Wal-Mart could deserve a spot in your portfolio, too.