NASCAR superstar Jeff Gordon posed with the winner's trophy at the Indianapolis Motor Speedway last year. Gordon, whose net worth is believed to be well over $100 million, is set to retire from full-time racing after the 2015 season. Source: Jeff Gordon/Hendrick Motorsports.

Just what is NASCAR superstar Jeff Gordon's net worth? And where did it come from?

Gordon, of course, is one of the top stock-car drivers of all time. He has been a leading driver in NASCAR's top Sprint Cup series ever since he came in fifth in the 1993 Daytona 500, the beginning of a campaign that would make him the series' Rookie of the Year. 

He has won the Sprint Cup series championship four times, and he's third on the series' all-time wins list with 92 (and counting).

But at age 43, Gordon has said that he's winding down: 2015 will be his last year. So how much money has he made? Let's see.

Where Jeff Gordon's income comes from
Like most racing drivers (and many big-name pro athletes), Gordon has two principal sources of income: the money he receives from his team, Hendrick Motorsports, and the money he receives from endorsements. That income has left him with a net worth of at least $150 million, according to TheRichest.com. Other sources put Gordon's net worth as high as $200 million.

Top finishes in Sprint Cup races bring cash prizes, so the income Gordon collects from his team is a mix of salary, equity, and his share of those winnings. He has an equity stake in his own Number 24 team, and he and team principal Rick Hendrick co-own another of the team's cars, the Number 48 driven by six-time (and counting) Sprint Cup winner Jimmie Johnson -- meaning Gordon has benefited financially from Johnson's considerable racing success, as well as his own.

Like all Sprint Cup cars, Gordon's trademark No. 24 is a rolling billboard for his sponsors. Here's the 2015 edition on the track at Talladega earlier this year. Source: Jeff Gordon/Hendrick Motorsports.

Gordon's sponsors include General Motors (GM 0.38%) -- his Sprint Cup cars have always been Chevrolets -- as well as 3M (MMM 0.97%), PepsiCo (PEP 1.05%), Panasonic (PCRFY), Axalta Coating Systems (AXTA 0.79%), and the AARP, for whom Gordon provides a platform for the "Drive to End Hunger" program.

DuPont (DD) was Gordon's lead sponsor for much of his career. These days, after Chevrolet, Gordon is probably most closely associated with the Pepsi brand, for which he has done a number of TV commercials over the years.

So how does all that play out in dollar terms?

Jeff Gordon's recent annual earnings
Forbes magazine, in its latest list of the world's highest-paid athletes, ranked Gordon 86th, with earnings from mid-2013 to mid-2014 of $18.7 million. The magazine broke that down to $13.7 million in winnings and $5 million from endorsements.

If that $5 million seems modest compared to what big-time NFL players and other superstar athletes can earn from endorsements, that's because it is. NASCAR drivers in general don't crack eight figures in endorsement money. Even telegenic and articulate drivers such as Gordon have limited mass-market appeal beyond the world of racing fans.

That 2014 income is not too far out of line with what he has been making over the past several years, according to Forbes, although it has declined a bit as his race victories have become less frequent. The magazine put his prior year's take at $18.2 million in mid-2013, $23.6 million in mid-2012, and $24 million in mid-2011. 

But the thing to remember is that Gordon has been earning at that level for quite a while. A mid-2004 edition of the Forbes list put his income for the prior year at $19.3 million. 

Given all that, and assuming Gordon has capable financial advisors (it appears he does), a net worth of $150 million or more seems very plausible.

Retirement is unlikely to leave Gordon in the poorhouse
Gordon signed a "lifetime" contract with the Hendrick Motorsports team in 1999, but he has let it be known that 2015 will be his last season as a Sprint Cup competitor. 

Gordon has two decades of success in NASCAR, but he's still only 43 years old -- and he has been lucky to escape serious injury during his career, although he has been plagued by chronic back pain off and on over the years. 

He's widely expected to be in and around racing for many years to come. Gordon is, after all, part-owner of two of the Hendrick team's cars, and he has hinted that might suit up and compete in the occasional race from time to time. 

He'll be getting a very solid income in his "retirement," in other words, to go along with what is probably substantial investment income from his existing fortune. In all likelihood, he'll be adding to that net worth total for many years to come.