Cable and Wireless is trying to reassure investors about its accounting policy regarding buying and selling network capacity.
The move follows a Financial Timesreport that the group had admitted using controversial accountancy techniques.
The report said C&W had used these to book notional profits generated by swapping free capacity with other groups.
However, analysts said the practice only represented a small part of sales; was not illegal; and was an ongoing business practice.
C&W said it bought and sold network capacity as part of its "normal commercial activities", stating: "Capacity sales are only treated as such where cash consideration passes and are separately reported in the company's published accounts. The group's accounting policy in respect of capacity sales is included in its published accounts."
It said capacity sales represented 4.5% of total turnover in the last half-year.
One analyst said the statement was reassuring. He said although the accounting practice was "not conservative", it was legal.
He added the practice was only illegal when a company had no reason to do it - for example, selling capacity and buying from a counterpart just to book revenues. This practice is known as "hollow-swaps".
Shares in C&W shares, which soared to more than £15 at the height of the tech boom and were around the 800p mark at this time last year, were down 5% or 13p at lunchtime at 227½p.
The share price has also been hit by recent concerns that C&W may issue another profits warning.
PA