Facebook, the social-networking service that's planning an initial public offering, said a patent dispute with Yahoo could have a material impact on its business.
Yahoo sued Facebook this month alleging that the site infringes Yahoo patents related to advertising, social networking, privacy, customisation and messaging, Facebook said yesterday.
The Menlo Park, California-based company said it hasn't yet issued a response to the lawsuit.
"This litigation is still in its early stages," Facebook said in the filing. "If an unfavourable outcome were to occur in this litigation, the impact could be material to our business, financial condition or results of operations."
Facebook, the world's most popular social-networking service, is grappling with more lawsuits over intellectual property.