The agency secured the business following a shoot-out against Profero and an agency pairing between Dare and i-level.
Grand Union will take responsibility for online creative executions and digital search optimisation for the InBev-owned lager brand. It will aim to drive traffic to stellaartois.com, the website created by the brand's above-the-line agency, Lowe.
The review, which began in May, encompassed both digital creative and media, although it is not yet clear what will happen to the latter portion of the business. Industry sources suggest that the client is still in talks with i-level, which was recently appointed to the digital media planning and buying for InBev's Beck's.
InBev is also in talks with agencies about its £16 million offline media planning and buying account, held by Starcom. It is not known whether these talks will lead to a full-scale media pitch.