BRUSSELS (Reuters) -The EU Commission on Monday said it had unconditionally approved Omnicom Group's ( OMC ) $13.25 billion all-stock deal to buy rival Interpublic Group.

The deal, announced last December, merges the world's third-largest ad buyer, Omnicom ( OMC ), with the fourth-largest which is Interpublic.

It would create the world's largest advertising agency as traditional players look to better compete with Big Tech firms amid the accelerating use of AI.