Mobil 1, the primary sponsor for Tony Stewart, said its funding for the three-time NASCAR champion remains unchanged.
An upstate New York grand jury on Wednesday declined to charge Stewart for the Aug. 9 death of Kevin Ward Jr. The sprint car driver died when he was struck by Stewart's car as Ward walked on the track.
Mobil 1 said in a statement: "The accident has been a terrible tragedy for all involved and our thoughts remain with the Ward family and Tony Stewart."
Bass Pro Shops and Rush Truck Centers, two of Stewart's other top sponsors, both strongly supported the driver when he made his return to racing after three weeks in seclusion.
The CEOs for both companies stood shoulder-to-shoulder with Stewart at his car before the race.