The Seattle-based networking company said a special committee of its board determined that it will have to restate past results to add $23 million to stock-based compensation costs. The company said it plans to file official results as soon as possible and to review internal procedures.
F5 said it is continuing to cooperate fully with both the Department of Justice and the Securities and Exchange Commission in their respective inquiries regarding the company's historical stock option practices.
F5 said fourth-quarter earnings were 58 cents a share on an adjusted basis, up from 50 cents a year ago and 3 cents ahead of the Thomson Financial analyst consensus estimate.
After falling $1.68 during regular trading to $65.49, F5 fell an added 9 cents in after-hours trading.