PARIS: Global adspend levels will decline by 9.9% this year, returning to modest growth of 0.5% in 2010, according to the latest forecast issued by ZenithOptimedia.

The media agency network has revised its previous estimates, made in July, of a drop of 8.5% in 2009 and growth of 1.6% over the following 12 months.

A weaker than expected first half of this year was the main reason for this adjustment, but Zenith also suggested the decline appears to be "bottoming out".

"We are still confident that the second half of the year will be much less painful for the ad market than the first half and expect the market to hit bottom before the end of 2009," it said.

"The second half of the year is developing in line with predictions, demonstrating clear improvements in the rate of decline."

More specifically, developed countries, including North America, Western Europe and Japan, will see adspend levels contract by 2.9% in 2010, before recording an improvement of 1.5% in 2011.

By contrast, developing markets are set to deliver growth of 7.8% in 2010, and 9.8% in 2011, as these nations increase their overall proportion of spending.

"Developing markets' share of global ad expenditure is rising rapidly: we forecast it to reach 35% in 2011, up from 29% in 2008," Zenith reported.

Overall, the Publicis-owned firm said 27 developing markets will enjoy growth this year, reaching 52 in 2010.

Data sourced from Wall Street Journal/Daily Telegraph; additional content by Warc staff