Ad giants abandon $35B merger

Omnicom Group and Publicis Groupe have called off their merger, citing "difficulties in completing the transaction within a reasonable timeframe."

According to CNNMoney, the $35 billion merger would have resulted in the largest advertising company the world has ever seen.

Most advertising agencies around the world are owned by one of four holding companies. Omnicom and Publicis are two of them; the other two are WPP and Interpublic.

Read more from CNNMoney.