A day trader in the US, Fred Moldofsky, has been charged for posting a fake Lucent Technologies' profit warning on the internet, which initially dragged the stocks down 3.6% - a drop of $7.1bn.

The stock price subsequently recovered as Lucent worked with Yahoo!, where the fake online warning was posted, and the Securities and Exchange Commission to limit the day trader's damage, said Lynn Newman, spokesperson at Lucent in Murray Hill, New Jersey.