The company blames short-seller investors – those who sell shares in a company in the hope of buying them back at a lower price – accusing them of trying to manipulate the market.
According to reports, the fax entitled "Running on Empty" began circulating in the City last week, alleging that the on-line retailer was running out of cash.
It had an immediate impact, causing the price of shares in Lastminute.com to fall by around 7%. The share price had previously risen, following the company's report on 11th February that it had suffered only a £1.8 million loss in the last three months of 2004, instead of an anticipated £4 million loss.
Company CEO Brent Hoberman confirmed that the rumours contained in the fax were inaccurate and that the incident had been reported to the financial regulator.
"It is another case of market abuse where people are profiting from wrong information," he told the BBC.
He added that the company has existing cash reserves of £30 million, and an unused £20 million overdraft facility.