Sorrell's note of caution

WPP chief executive Sir Martin Sorrell is expected this week to warn that the global advertising market could see growth slow during 2005.

Two major factors have boosted advertising this year - the Olympics and the American presidential election.

Sorrell will announce his third-quarter trading statement on Tuesday and is likely to be cautious about future prospects for advertising ahead of the US election in nine days. The market is expected to grow by about four% this year.

However, WPP is likely to report like-for-like revenues in the third quarter, up about five% to more than £1 billion, and it is expected to confirm that it is on course to achieve annual margins of 13.8%.

WPP's strongest performance is likely to have been in Asia, the Pacific region and the Middle East.