Zenith and GroupM trim global advertising spend forecasts

LONDON (Reuters) - Two leading forecasters of global advertising trends trimmed their predictions for growth in ad spending this year, due to a sharp slowdown in Russia and economic weakness in the euro zone. Zenith Optimedia, owned by advertising agency Publicis, had downgraded its forecasts in September and cut them again on Monday. They now expect global advertising expenditure to rise 5.1 percent in 2014 and 4.9 percent the year after. The forecasts compare with September's downgraded expect