Credit Suisse have backed the Formula One racing team for eight years
Formula One racing team BMW Sauber have lost one of their main backers ahead of the new season after Credit Suisse opted not to renew their deal.
That contract ended in 2008 and Credit Suisse will now "focus on regional sporting and cultural activities".
"We think that the team is on a good path and so now is the right time to say goodbye," continued the statement.
A BMW Sauber spokesman told BBC Sport that it would have "no impact" on the team's budget for 2009.
"It will have absolutely no influence on that," he said.
"The budget for 2009 is fixed, we are happy with it, and we move on as always.
"The search for new sponsors is ongoing, as it always is, but it is not something we can set a deadline on.
"We are having some interesting discussions with various parties and we will see how they develop."
Credit Suisse was the main sponsor of Switzerland's privately owned Sauber race team from 2001 to 2005 and stayed on when the outfit was taken over by BMW at the start of 2005.
Last season was the team's best so far, with BMW Sauber celebrating its first win at the Canadian Grand Prix and finishing third in the constructors' championship.
BMW Sauber are due to unveil their 2009 car on Tuesday, after a winter in which F1 has been forced to face harsh economic realities.
2009 CAR LAUNCH DATES
20 Jan: BMW Sauber
9 Feb: Red Bull
TBC: Toro Rosso, Force India, former Honda team
The sport's bosses have repeatedly called for teams to implement cost-cutting measures, and new regulations for the 2009 season include limits on testing and other rules to curb spending.
Honda pulled out of F1 in December, but the sport's remaining teams have all voiced their commitment to shaping a more cost-effective future for the sport.