However, both believe that the worst of the recession is now behind them - Publicis claimed £2.3 billion-worth of new business, while Interpublic insisted it was back on course following earlier accounting scandals.
Interpublic, which owns the McCann-Erickson, Lowe and FCB networks, blamed the fourth-quarter loss on restructuring charges of £22.l million and a loss of £21.7 million relating to the sale of the Brands Hatch motor-racing circuit.
Although the group reported a 2.2 per cent revenue rise for 2003 to £3.3 billion, it reported a net loss of £258 million compared with a £56.8 million profit in 2002.
But David Bell, the Interpublic chairman, said: "The significant success we have experienced in resolving the company's problems, in strengthening the balance sheet and in bolstering margins, makes it clear that the first phase of our turnaround will soon be behind us."
He added that there were signs of a revenue resurgence at McCann.
Meanwhile, Publicis, whose operating companies include Saatchi & Saatchi, Leo Burnett and Fallon, revealed a 29 per cent rise in operating income to £386 million. Net profits rose by almost 22 per cent to £184 million last year.
Maurice Levy, the Publicis chairman, confirmed that the group's aim was to establish solidly a 15 per cent operating margin and improve its financial structure.
"Our 2003 objectives were extremely ambitious," he said. "Without exception, they were achieved or surpassed. They included the successful integration of Bcom3, the reorganisation of our health communications offering and the repositioning of our specialised agencies and marketing services, while improving our profitability and balance sheet."