British directories firm Yell soothed the nerves of investors today as it continued its battle against “fierce” competition in the United States.

Yell lost £800m of its market value today after warning that its Yellow Book business in United States faced intense competition.

A warning about intense competition in the United States caused shares in directories group Yell to dive by as much as 17% today.

The owner of Yellow Pages, the UK version of the Golden Pages, bolstered it US operation today with a deal worth £829m (€1.2bn) for a leading directories publisher in California and Texas.