America has more millionaires than you think. Here’s how most of them got rich.

(CBS) — The richest person in your town probably isn’t a technology entrepreneur or a hedge fund manager. More likely, it’s the dentist who runs six offices or the HVAC contractor whose trucks you see everywhere, according to economists Owen Zidar and Eric Zwick.

These “stealthy wealthy,” as the duo describes them in their new book, “The Everywhere Millionaire,” typically get rich the old-fashioned way — through hard work over many years. And there are plenty of them in the U.S., with roughly 5 million households worth at least $5 million and holding combined wealth exceeding 13 times that of the Forbes 400, their research shows.

The findings, based on the economists’ deep dive into Treasury and IRS data that matched tax records to individual businesses and their owners, show that the path to great wealth in the U.S. typically isn’t through a regular paycheck. Instead, it’s through ordinary enterprises that often benefit from the same tax breaks and structures — “pass-through” businesses such as sole proprietorships and partnerships.

“This is not just a story about wealth being on the coast, Silicon Valley and finance,” Zwick, an economics professor at the University of Chicago Booth School of Business, told CBS News. “This is a much broader phenomenon, and also much closer to home for a lot of Americans.”

To be sure, the stock market boom has also minted a growing number of 401(k) millionaires, but Zwick and Zidar are focused on people who have amassed wealth far beyond what even dedicated savers have been able to sock away. These “everywhere millionaires” include 3 million owners of private businesses, with an average wealth of about $25 million, they found.

“Elon [Musk] is very rich, but the Forbes 400 is 3% to 5% of total household wealth in the U.S., and this group is just so much bigger, and that’s consequential for understanding the economy,” Zwick said.

The millionaire next door?

The new research is reminiscent of the 1990s bestseller “The Millionaire Next Door” by Thomas Stanley and William Danko, which found that many millionaires were average Americans who built their wealth through careful saving and investing. These millionaires were more likely to drive a used car than a flashy luxury car, and were less likely to live on Park Avenue than on Main Street, according to the book.

The millionaires who are the subject of Zwick’s and Zidar’s research aren’t generally as unassuming as those studied by Stanley and Danko, with the economists finding that many of these wealthy business owners aren’t shy about enjoying the fruits of their prosperity. Yachts, large houses and other extravagances are common, they found.

At the same time, their businesses are of the typical brick-and-mortar variety, rather than the headline-grabbing wealth associated with Silicon Valley and Wall Street.

“You’re walking down the street, you look at a truck that’s delivering beer, and if you look on the door, you see the name of the beer distributor, and then you go look them up, and you’re like, ‘Oh, that’s an everywhere millionaire,'” Zwick said. “And you start to see them everywhere like that.”

Who are America’s everywhere millionaires

The research also examined the traits of the typical millionaire, tracking whether they inherited their businesses or wealth, for instance, or if they were more likely to have college degrees. The pair found that about three-quarters of these millionaires started their own businesses, while the vast majority didn’t inherit money.

“The typical everywhere millionaire is 62, married,” Zwick said. “They’re more likely to be a college graduate, but not that much more likely than the general population.”

Their business is also their day job, and they’re not necessarily retired even though they’re in their 50s, 60s or older, he added. “Often they’re still quite obsessed with what they’re doing,” he said.

One typical millionaire profiled by the economists is Dick Portillo, who grew up poor in a Chicago housing project and started a hot dog stand in 1963 with a $1,100 investment. Portillo grew the business into a large regional chain, eventually selling it to Berkshire Partners for $1 billion.

Many of these business owners are driven chiefly by a desire to be their own bosses rather than to become rich, Zwick said.

“Freedom, independence, is almost more important to a lot of them when they’re starting — Portillo similarly — than ‘Oh, this is going to make me hugely rich,'” Zwick said.

Pass-through businesses

One common characteristic of many such millionaires is their use of pass-through businesses, such as LLCs or sole proprietorships, that provide a lucrative tax benefit to their owners. The tax code allows profits from these businesses to flow to the owner’s personal tax return, avoiding the double taxation of corporate taxes.

Such arrangements also allow pass-through businesses to deduct 20% of that income from their taxes, allowing owners to avoid paying income taxes on a portion of their earnings. Those benefits help owners accumulate wealth in ways most W-2 employees can’t emulate.

“You pay lower tax if you’re getting your income through one of these businesses, even if your labor is going into running the business,” Zwick told CBS News. “It has made them richer than they otherwise would have been, and it’s an important part of the story of their growth over the last 40 years.”

Will AI change this path to wealth?

Zwick said he believes his findings show that the American Dream “is more alive than most people think.”

He added, “The prevailing narrative is very pessimistic relative to our reading of the data, but it’s not necessarily where people are looking.”

With artificial intelligence prompting speculation about the future of work, Zwick thinks opportunities to build wealth will continue to abound in the U.S.

“The problems that these people are solving are tactile, they’re tangible — they’re problems that people experience every day,” he said. “Technology will change what these businesses look like, but these tactile, real-world problems are still going to be there. HVAC is still going to be a need.”

He added, “There’s a lot of room for people to take new technology but solve these old problems.”