By Robert Plummer
Business reporter, BBC News
Tiger Woods' extraordinary golfing prowess has made him the wealthiest sportsman in the world - but behind every great sportsman these days, there is always an array of big businesses.
Is Tiger Woods' reputation hanging by a thread?
Nike has been Woods' biggest sponsor since the start of his career, signing its first contract with him as long ago as 1996.
Since then, other major companies have added their endorsements, including the Gatorade drinks brand and Gillette razors.
In fact, despite being the world's number one golfer, Woods makes far more money off the green than on it.
Last year, he earned $23m (£13.8m) from golf tournaments - a figure dwarfed by the more than $100m that his various sponsorship deals brought in.
So with his previously impeccable image now somewhat tarnished, amid continuing speculation about his private life following last week's car crash, his income is hugely dependent on how those sponsors are likely to react.
In the long term, it is unclear whether the 33-year-old star's apology to his family for his "transgressions" will restore his clean-cut reputation or simply add to the perception of guilt.
But so far, the picture is mixed. Nike, Pepsico, TLC Vision and Electronic Arts all issued statements on Wednesday to the effect that their relationship with Woods was unchanged.
Born: Eldrick Woods in December 1975 in Cypress, California
First major title: In 1997, less than a year after turning professional
Winner: Of 71 official PGA Tour events, including 14 majors
Described as world's most marketable athlete, sponsorship deals with GM, Nike and others
Jet plane rental firm Netjets, a subsidiary of billionaire Warren Buffet's Berkshire Hathaway investment firm, went further, saying: "Tiger Woods is one of the premiere athletes in the world and we are proud to have him involved with Netjets."
On Monday, Gatorade wished Woods well as he recovers from his injuries and said: "Our partnership with Tiger continues."
Others sound less committed. Gillette says its marketing strategy is unchanged, but has left open what might happen in the future.
More ominously, however, several other sponsors have yet to pronounce at all on the matter.
This week, companies such as watchmaker Tag Heuer and IT firm Accenture have continued to run advertising campaigns in the US media featuring Woods.
But they, and other big backers including telecoms giant AT&T, have so far been "unavailable for comment" on whether he still enjoys their full confidence.
Woods's woes have already had a direct impact on his relationship with at least one sponsor.
On Monday, he withdrew from his own tournament, the Chevron World Challenge, blaming injuries from the crash.
The event at Sherwood Country Club in California is a charitable one, staged by the foundation that bears the golfer's name and backed by one of the world's energy giants.
According to Greg McLaughlin, president of the Tiger Woods Foundation and tournament director, the company put a brave face on the outcome.
He said Chevron would have liked Woods to be part of the tournament, but added: "They respect his decision, they support his decision."
Until his motoring misadventure, Tiger Woods was at the peak of his prestige - and earning power.
In September, according to Forbes magazine, he became the first athlete in history to earn $1bn in the course of his sporting career.
His success as a black player in a traditionally white sport has been a huge personal achievement.
But it has also raised the profile of golf itself, taking it to new heights of popularity among audiences who would never previously have paid attention.
That has, in turn, upped the stakes for the sport - and fans and players alike are watching to see what happens next.
As fellow US golfer John Daly has said: "We need him more than anyone else on tour, the way the economy is.
"Tiger is the biggest asset the tour has had for a long time. Golf needs Tiger."