Shares in British telecoms equipment-maker Marconi sank to their lowest since the company was created in its current form after a US rival cut its second-quarter financial outlook overnight.
The company also said today it had sold its remaining stake in French energy and transport company Alstom SA for euro 387 million.
US telecoms equipment maker Tellabs said it was being severely affected by a slowdown in the US economy and a huge reduction in spending by telephone and Internet service customers.
"The numbers from Tellabs were pretty dramatic and this has put Marconi under a lot of pressure... the profit warnings keep coming from across the Atlantic and there is nowhere to hide," said one London-based technology analyst.
In London this morning the stock was amongst the FTSE 100 index's worst performers, down 7.14 per cent at 247p. The stock has lost 63 per cent of its value in the year to date, underperforming the FTSE All Share Information Technology Index by 60.5 per cent.
Its woes were compounded today by a shock warning by German chipmaker Infineon AG, which sent tech stocks tumbling.
Marconi was created as a telecoms specialist in 1999 when the former GEC was split in two.