Ubisoft Entertainment is a French computer and videogame developer and publisher with headquarters in Montreuil-sous-Bois, France. It was founded in 1986 by five brothers, of which Yves Guillemot serves as chairman and CEO. The company consists of 26 studios spread across 18 countries. As of 2011, it was the third most valuable independent videogame publisher in the world, and the second largest in terms of in-house development staff with over 6,900 staff worldwide. Ubisoft also ranked 26th on the list of the largest software companies in the world. Their most famous games and franchises are, The Prince of Persia: The Sands of Time series, Rayman franchise, Assassin's Creed franchise, Brothers in Arms and the Tom Clancy franchise which includes the Rainbow Six, Ghost Recon and Splinter Cell series.