Facebook hits back with counterclaim saying Yahoo infringed 10 patents

Facebook has accused Yahoo of infringing 10 of Facebook’s patents, according to a court filing.

The counterclaim from Facebook, filed in a San Francisco federal court, comes after Yahoo sued Facebook for patent infringement last month. A Yahoo spokesman could not immediately be reached for comment.

Facebook, the world’s largest internet social networking service, is preparing for an initial public offering that could value the company at up to $100bn (€75.5bn).