In December, six weeks after hiring Interpublic Group's DraftFCB as its new advertising agency, Wal-Mart fires both Draft and Wal-Mart senior vice president Julie Roehm, who led the agency search.

Roehm reportedly attended an expensive dinner paid for by Draft at a hip Manhattan restaurant, in violation of a Wal-Mart policy that prohibits employees from accepting gifts from vendors.

The move is expected to delay Wal-Mart's efforts to shift from a mass advertising strategy to one that tailors pitches to specific demographic groups, seen as key to reversing its slumping sales.