The slowdown in the rate of WPP's revenue decline led to an increase in its share price, which rose by 4.2 per cent to 568p in early trading today.
Sir Martin Sorrell, the company's chief executive, attributed the recovery to improved consumer confidence, which was gradually filtering through to clients' advertising budgets.
In its third-quarter trading update, WPP pointed out that its revenue growth figures for July, August and September were "less worse" than those of April, May and June.
Sorrell predicted that the slowdown in revenue decline will continue into 2010, although he pointed to the fragility of the recovery, stating: "There is little doubt that consumer and corporate confidence has recovered somewhat from the panic levels of the fourth quarter of 2008 and first quarter of 2009.
"Confidence, however, remains fragile amongst consumers, because of the shadow of high unemployment levels and amongst corporates, because Armageddon and Apocalypse Now were barely avoided in September 2008.
"Whilst the hearts of CEOs and CMOs are stronger and their minds clearer, increased confidence is still not transferring to their cheque-writing hands."