A special committee of Apple's board of directors said its three-month investigation concluded that Steve Jobs "was aware" of irregular backdating of options for some executives, but that he personally did not benefit from this.

The panel found that stock option grants made on 15 dates between 1997 and 2002 "appear to have grant dates that precede the approval of those grants", meaning that they could have given extra money to those receiving the options.

"The investigation raised serious concerns regarding the actions of two former officers in connection with the accounting, recording and reporting of stock option grants," Apple said in a statement. It said that details will be provided to the US Securities and Exchange Commission.

Nationwide scandal

"I apologise to Apple's shareholders and employees for these problems, which happened on my watch. They are completely out of character for Apple," Jobs said in a statement on Wednesday.

Apple is one of the most prominent companies caught in a nationwide stock options mishandling scandal in the US and said its investigation did not uncover any misconduct by any member of Apple's current management team, but that it did raise "serious concerns" regarding the actions of two former officers.

'Backdating issues'

More than 100 other companies nationwide are entangled in similar stock-option trouble. In most of those instances, companies have traced their problems to "backdating" issues.

Under this practice, insiders could make the rewards more lucrative by retroactively pinning the option's exercise price to a low point in the stock's value.

Apple has said it will have to restate some earnings as a result, which could wipe out some of the profits generated during the most prosperous stretch in Apple's 30-year history resulting from iPod sales.