Financial analyst discusses risky Omnicom and Interpublic merger with potential dis-synergies, talent conflicts, and stagnant revenue, making shares a hold.

The deal of the decade redefines revenue dynamics, global markets, and service mix. Omnicom’s acquisition of Interpublic Group is on track to create the world’s largest agency group by total revenue, making a big splash this week after the proposed deal was kept mostly under wraps.