Bill

Bill Gates. Photo Credit: UK Department for International Development-via Wikimedia Commons

Each year Forbes puts out its list of the 400 richest people in America. Last year an entrant needed a minimum net worth of $1.55 billion just to crack that list, which was up from $1.3 billion in 2014 and the highest since Forbes began tracking American wealth in 1982. So high is the net worth of the top 400 Americans that there were actually 113 billionaires that didn't qualify for the list this year.

There's usually not much change at the top of the list of America's wealthiest. In fact, Bill Gates has topped the list for 21 straight years while Warren Buffett has claimed the number two spot since 2001. Rounding out the top five are Larry Ellison, and Charles and David Koch. Combined the top five hold nearly $280 billion in wealth, which for perspective is enough money to fund the entire U.S. federal budget spending on education for nearly three years. Here's how these five men amassed so much wealth.

One common theme
Bill Gates is not only the richest American, but for 16 of the past 21 years he has been the richest man in the entire world. According to Forbes he's worth $79.4 billion despite the fact that he has given away nearly $30 billion of his wealth to charity over the years. It's wealth that's driven by the fact that he had long been the largest shareholder of Microsoft (NASDAQ:MSFT), which he co-founded in 1975. With the stock up more than 46,000% since going public in 1986, Microsoft didn't just enrich Bill Gates, but also created two other billionaires and 12,000 millionaires just among the company's employees.

Warren Buffett took a slightly different route to the top as he shrewdly invested his way to become the second richest American. His wealth journey started in 1962 when Buffett acquired a struggling textile company called Berkshire Hathaway (NYSE:BRK-A)(NYSE:BRK-B) and subsequently turned it into a holding company to acquire other businesses. Today, Berkshire is a conglomerate with core holdings in energy, insurance, and railroads and now has the fourth largest market valuation among public companies. It's Buffett's stake in the business that's the driving force behind his vast wealth, estimated by Forbes to be $66.3 billion.

Next up is Larry Ellison, who followed Bill Gates path to the top-five as he founded the predecessor to database giant Oracle (NYSE:ORCL) in 1977. Ellison's initial investment to found the business with two partners was a mere $1,200 with the partners chipping in another $800. It's an investment that really paid off as Ellison's net worth is an astounding $50.5 billion according to Forbes due largely to Oracle's surging stock price over the years.

Rounding out the top five are the Koch Brothers. David and Charles both own a 42% stake in privately held Koch Industries, which is the second largest private company in America by revenue. It's a business that's more in the mold of Warren Buffett's Berkshire Hathaway as the conglomerate owns businesses operating in the energy, agriculture, and consumer goods section of the economy. However, unlike the others on the list it's not a business that the pair founded as the predecessor to Koch Industries was founded by their father Fred in 1940. That said, the brothers were the ones that turned the business into what it is today giving the Koch Brothers a net worth of $41.7 billion apiece according to Forbes.

Key takeaway
If there is one common theme among the five richest Americans it's the fact that their wealth stems from their direct ownership in a business that they held for decades. That makes for a clear lesson for those who would like to see their own net worth rise to new heights: Own a business. That said, the business doesn't need to be one that's founded from scratch as Warren Buffett and the Koch Brothers made quite a lot of money by investing in -- and holding on to -- great businesses founded by others. In fact, we can amass great wealth by investing in an ownership stake of great businesses, or compounding machines as Buffett likes to call them, via the stock market and holding those stakes for the long-term.

Matt DiLallo has the following options: long January 2017 $135 calls on Berkshire Hathaway and short January 2017 $145 calls on Berkshire Hathaway. The Motley Fool recommends Berkshire Hathaway. The Motley Fool owns shares of Oracle. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.