Red Bull is holding a UK media planning and buying review.
The energy drink brand has worked with independent shop AMS since 1996 and the agency is repitching.
Earlier this year, Red Bull appointed Starcom to its North American media account, replacing Carat.
Red Bull kicked off a search for an agency to create a global advertising campaign to support its incubator programme for social entrepreneurs in May, but the review has since been put "on hold".
Red Bull was unavailable for comment.
The brand creates much of its content and communications through Red Bull Media House. It also works with Somethin’ Else on a project basis.