General Motors Corp. consolidates national advertising for its Buick, Pontiac and GMC brands in the U.S. under Leo Burnett, effective Oct. 1.

The advertising firm currently handles Pontiac’s national advertising, but up to now the Lowes unit of Interpublic Group has taken care of GMC creative, and McCann Erickson group has managed Buick efforts.

GM calls the shakeup “purely an operational business decision,” as it works to strengthen the single retail channel that the three brands now occupy.

“Although we have made a lot of progress to date in aligning these three brands as a single channel, we still have work to do,” says Jim Bunnel, General Manager, Buick Pontiac-GMC, in a statement.

“It’s time to move to the next level, and we believe that having one dedicated agency will help us get there.”