Mgm

Metro-Goldwyn-Mayer Inc. is an independent, privately-held motion picture, television, home video, and theatrical production and distribution company. The company owns the world's largest library of modern films, comprising approximately 4,000 titles, and over 10,400 episodes of television programming.

Private Company - acquired on April 8th 2005 by Sony, Providence, TPG and Comcast.

Sources:
http://www.mgm.com/corp_main.php
http://www.sony.com/SCA/press/050408.shtml