What's the wealth-making secret of the world's billionaires? For investors on the list, it's sticking to a strategy that plays to their inherent strengths. For many of the others, including five of the top 10, its entrepreneurship.

Oh to be an owner
You know the list: Microsoft's Bill Gates and Paul Allen, Oracle's Larry Ellison, and Dell's Michael Dell are the four most recognizable names on Forbes' latest list of the nation's richest. Real estate mogul Sheldon Adelson and his $20 billion fortune, composed mostly of stock in Las Vegas Sands, ranks third and rounds out the list of self-made billionaire entrepreneurs in the top 10.

But there are many more. Boston Scientific (NYSE:BSX) co-founder John Abele ranks 140th with a $2.2 billion fortune. Meanwhile, chip champion Gordon Moore, who co-founded Intel (NASDAQ:INTC) with Robert Noyce in 1968, is 77th with $3.4 billion. And Public Storage (NYSE:PSA) founder B. Wayne Hughes ranks 61st with $4.1 billion.

Invest with owners
If you're feeling envious, I don't blame you. Wouldn't it be great if we were all billionaires, unencumbered by the need for money? Of course it would be. But that's not how the world works.

Still, I find it reassuring that, as rich as Bill Gates and Paul Allen are, the bulk of their wealth came from staying invested in the company that brought them to the billionaires' ball. Why? Because anyone with a brokerage account could have enjoyed similar percentage gains.

In fact, many did. So great is the story of Microsoft's ability to generate wealth that it has a name -- the uprising of the so-called "Microsoft millionaires." At least hundreds of them must still exist. Consider this chart. A $1,000 investment in Microsoft in 1990, four years after its debut on the Nasdaq, would be worth $50,000 today.

Searching for the next Microsoft
That's why Motley Fool Hidden Gems co-advisors Tom Gardner and Bill Mann focus on the stocks of up-and-coming firms in which the managers own a significant stake. Some of their best performers still feature heavy insider ownership.

Consider laser-components maker II-VI (NASDAQ:IIVI), which Tom singled out in the August issue for its smart acquisition strategy. The stock is up more than 72% since, enriching insiders who still own nearly 20% of the company.

Then there's MDC Holdings (NYSE:MDC), which is a homebuilder based in Denver. Bill recommended the stock for the September issue, and it's up more than 30% since. Meanwhile, CEO Larry Mizel still owns more than 15% of the business.

So don't envy the billionaire owners. Invest alongside them. They're the ones who really have the best chance to create the next Microsoft and make you millions in the process. And if you'd like Hidden Gems to help you identify some promising prospects, click here to join the service free for 30 days.

This article was originally published on Oct. 12, 2006. It has been updated.

Fool contributor Tim Beyers, owns shares of Oracle. Microsoft, Dell, and Intel are Motley Fool Inside Value picks. Dell is also a Stock Advisor pick. The Motley Fool's disclosure policy always takes ownership.