Hewlett-Packard has been hit with a tax notice that could cost it $660m, the company said in a regulatory filing made just before the holiday weekend.

The world’s biggest computer maker said the Internal Revenue Service sent it a “notice of deficiency” on July 30 saying that it owed back taxes of $92m from fiscal 2004 and 2005, along with a $5m penalty. The finding follow an audit that began in 2007.