The firm, led by Martin Sorrell, said its like-for-like sales were up 6.1 percent in the first half of the year, and up 5.9 percent for the first 7 months, putting it broadly on track for its recently upgraded annual forecast of at least 6 percent growth.
WPP, whose ad agencies include JWT and Ogilvy & Mather, upgraded its 2011 outlook in April after it outperformed peers in the first quarter.
However shares in the group fell around 25 percent in the last 7 weeks, underperforming the FTSE 100 Index by 11 percent, as investors feared that the sluggish economy in the United States and eurozone debt crisis would hit corporate spending.
WPP said its revised forecast for the year so far indicated very similar levels of like-for-like revenue and gross margin growth to the first 7 months.
Any slowdown in the United States is likely to be balanced by faster growth in Britain, western continental Europe, and faster growth in Asia Pacific, Latin America, Africa and the Middle East, and central and eastern Europe.
In summary, so far so good in 2011, with forecasts in reasonable heart, but there are storm clouds and we still have to see how the latest stock market crisis affects consumer and client thinking and actions, it said.
Any impact may not be felt until 2012.
Plans, budgets for 2012 and forecasts will, therefore, be made on a conservative basis and considerable attention is still being focused on achieving margin and staff cost to revenue or gross margin targets.
(Reporting by Kate Holton)