Shares in Cisco Systems fell more than nine per cent in after-hours trading on Wednesday, fuelling concern that the financial crisis in US banks could limit IT spending.
The sub-prime mortgage has hit major US banks, which are among the world's biggest purchasers of IT.
As a result, US business growth is expected to remain unpredictable, said Cisco chief executive John Chambers, in a conference call to discuss the group's first quarter results.
Cisco shares lost 9.1 per cent to $29.77 (£14) after Wednesday's close, having risen more than 20 per cent this year.
Wednesday's earnings announcement unveiled a 37.1 per cent year-on-year rise in net income to $2.2bn (£1bn) and was followed by a three per cent share price slip.
