Multiple people familiar with the decision say a team official traveled to Michigan Speedway and told industry leaders Sunday of the impending move. The people spoke on condition of anonymity because an official announcement has not been made to team employees.
Red Bull is both the owner and sponsor of the two-car NASCAR team. The team has struggled since its 2007 entry into NASCAR and consistently has been plagued by rumors and speculation that the Austrian ownership group will leave the auto racing series.
No reason for Red Bull's leaving has been given, but the energy drink markets to the 18-to-34 age group — the demographic NASCAR has consistently lost in its current ratings slide.
"Red Bull Racing Team is currently seeking outside investors as we evaluate next steps in the NASCAR Sprint Cup Series," the team said in a statement.
"We are not at liberty to comment on details while negotiations are under way. Red Bull fully supports NASCAR for the remainder of the 2011 season as we fight for victories and a position in the 2011 Chase for the Sprint Cup."
Kasey Kahne posted on his Twitter page Monday that he had just heard the news and vowed his No. 4 Toyota team would finish out the season strong. He's on a 1-year contract with Red Bull until he moves to Hendrick Motorsports at the end of the season.
"All I can say is the (No.) 4 RED BULL team is still going to do all we can to win this year. We know we can!!" Kahne tweeted.
The team had a horrendous debut season in 2007, when Brian Vickers failed to qualify for 13 of 36 races. He finished 38th in the final Sprint Cup standings.
AJ Allmendinger missed 19 races that year and was 43rd in the final points.
Jay Frye, a respected team manager in NASCAR, was brought on the next season as general manager, and the team slowly improved. But Allmendinger was let go late in 2008 for Scott Speed, who had been let go from Red Bull's Formula One team.
Like Allmendinger, Speed was not ready for NASCAR's top level, and the lack of experience in Red Bull's second driver hindered Vickers' development. Speed was let go at the end of last year and is currently suing Red Bull.
Vickers won a race in 2009 and made the Chase for the Sprint Cup championship, only to be sidelined most of last year with blood clots. He's back this season, and the team has Kahne on loan from Hendrick Motorsports, but still isn't among the top NASCAR organizations.
Kahne has five top-10 finishes and is 19th in points; Vickers has five top-10 finishes and is 24th in points.
Kahne moves to Hendrick Motorsports at the end of this year, and Vickers is in the final year of his contract. It's not clear what will happen to development driver Cole Whitt, who is ranked second in the Trucks Series standings, or to the Red Bull employees.
It's possible Frye could line up investors to buy the race team from Red Bull. He's twice before run race teams that way with varying success. Frye put together the part-time deal that convinced Mark Martin to hold off on retirement, and his teams were successful until they succumbed to sponsorship issues.
Red Bull, meanwhile, also owns a pair of two-car Formula One teams. Current points leader Sebastian Vettel is the reigning world champion and has won five of seven Grand Prix races this season.