The company’s share price fell 12.11% to $18.14 on the news, which could lead to new charges against the New York’s company’s former CFO David Kreinberg and CEO Jacob Kobi Alexander. Kreinberg has already implicated Alexander in the stock options fraud. Alexander, who fled the US as the scandal broke, is currently fighting his extradition from Namibia.

Comverse said it has identified errors in the recognition of revenue related to certain contracts, errors in the recording of certain deferred tax accounts, and the misclassification of certain expenses in earlier periods. It said that areas of financial reporting under investigation include the possible misuse of accounting reserves and the understatement of backlog in fiscal 2002 and prior periods.

Comverse has already admitted that the actual dates of measurement for stock-option grants for accounting purposes differed from the recorded grant dates and is close to completing the stock option inquiry.

But having persuaded Nasdaq to issue a stay of its original decision to set a deadline of September 25 to file its annual report for the fiscal year to January 31 and for the first quarter to April 30, it now faces a further delay to correct the new accounting errors.

Comverse said it is unable to estimate the time it will take to complete the necessary restatements and whether the delay will result in a lifting of the stay and a delisting of the company’s shares from Nasdaq.

This would create an immediate problem in that holders of $419.6m of convertible debt would then have the right to demand the company repays them with cash. This would not be an insurmountable problem as Comverse has cash and equivalents of $1.85bn.

But the difficulties do leave it vulnerable to a takeover. Comverse has lost 38% of its stock market value since its option difficulties were revealed in March, and its current market capitalization of $3.68bn may well tempt a bidder, particularly as its cash pile would reduce the price of a purchase.

Hewlett-Packard Co has just closed its $4.5bn acquisition of Mercury Interactive Corp, which had admitted stock options fraud.