But the crash could also spell changes for Stewart, who is one of NASCAR's most popular drivers, and who appeared to actually hit the throttle as he struck Kevin Ward Jr., according to some witnesses quoted by The New York Times.
Investigators say he is cooperating, and there is no evidence against him.
Unless he is convicted of a felony, Stewart probably will not suffer commercially, experts told CNBC.
"I don't think that there are people out there who would stop supporting [a company] because of its relationship with Tony Stewart," said Ramsey Poston, a former NASCAR executive and president of public relations company Tuckahoe Strategies. "I just don't see it rising to that level at all."
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In fact, Poston said, Stewart is so valuable to his primary sponsors, which include Bass Pro Shops and Mobil 1, that they will be very careful before breaking from the lucrative partnership.
"Sponsors depend on drivers who can carry the message, help develop a brand, and sell a product. And there are few drivers who do that better than Tony Stewart because of his passion and because he is genuine," Poston said.
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Stewart's sponsors should take a wait-and-see approach, said Bill Glenn, president of The Breakout Group, a consulting firm specializing in sponsorships. Without any legal trouble for Stewart, the companies attached to him cannot immediately know the public relations effects, he said.
Somewhat paradoxically, the crash could even be spun as a positive for the sponsors if they could become involved in any subsequent efforts to make racing safer, Glenn said.