The directories firm, which owns Yellow Pages and Yell.com, saw its shares fall 50.25p to 279.75p, which is below the 285p it was floated for in 2003 when it was spun out of BT. Its shares recovered slightly this morning and were up 1.79% to 284.75p.
The crash in its share price came despite healthy pre-tax profits, which were up 23.4% to £216.3m for the nine-months to December 31. Yell said that UK revenue increased 3.3% to £527m, driven entirely by a 49% increase in revenue by Yell.com, which offset the expected 4.4% decline in print advertising. Yell.com's revenue grew to £101.5m, with growth dominated by a 34.8% increase in search advertising.
John Condron, CEO of Yell, said: "These are good results fully in line with expectations in all our markets despite toughened trading conditions, particularly in the UK.
"We believe that we will grow across our markets at rates either similar to or higher than this year. This growth will be driven by the strength of our online businesses; the more flexible pricing we are introducing in the UK; the new approach to sales being rolled out in Spain; and the reinforcement of our proposition in the US."
However, the markets took the news of the new approach being taken in Spain and the change to UK pricing that Condron spoke of as evidence that the firm was more exposed that previously thought to a downturn.
Analysts said the UK slowdown upped existing concerns about the prospects of online competition from the likes of Google and Yahoo!.
The erosion of the classified markets could have a devastating affect on Yell if it is not able to meet the challenge from search advertising on services such as Google's Adwords.