Shares in RTL crashed today after the broadcasting giant joined the long list of companies warning of ad-related slowdowns.

The pan-European broadcaster issued a profits warning forecasting that earnings before interest, tax and depreciation will fall by 10%-15% this year, hurt by falling advertising markets. The thinly traded shares tumbled from Euros80 to Euros55, a fall of 27.5%.

In a statement it said "advertising markets have been tough. Visibility has deteriorated further and the phasing of recovery in advertising conditions cannot be predicted with any certainty."

Pearson the UK publishing group which owns a 22% stake in RTL, also blamed weak advertising markets for the 15% drop in full year profits that it is today forecast. Pearson reported a first-half loss of $195m (£137m).

RTL, which has stakes in RTL television channels in Germany, Belgium and the Netherlands, M6-Metropole Television in France and Channel 5 in the UK, has traditionally been Europe's largest broadcaster. However, the latest share price fall means that the company is valued at Euros8.35bn. That is a 68% drop compared with the Euros26.1bn the company was worth when the shares were floated simultaneously on the London and Brussels stock markets exactly a year ago Euros 171.5 each.