Omnicom Group is planning to axe up to 3,500 jobs globally. The cuts are expected to occur across the board, though it is not clear which of its agencies will be most affected.
The job losses will represent 5% of its 70,0000 workforce. Its main ad agency networks include DDB, TBWA and BBDO, while its media agencies include OMD and PHD.
It is believed that BBDO in the US could be heavily hit after losing the $60m (£40m) Pepsi business to TBWAChiatDay last month. BBDO had held the account for nearly 50 years.
The agency has also been affected by the troubled car industry. It was recently forced to cut over 20% of its staff in its Detroit office after client Chrysler signalled plans to reduce marketing activity.
In October, the marketing services group posted a third quarter net income of $213m, which was up slightly from $202m in the same period last year.
Last month, WPP chief executive Sir Martin Sorrell warned that job cuts would need to be made across its group in the more mature markets it occupies.