GameStop, a wholly owned subsidiary of Barnes & Noble, has filed for an initial public offering. The Grapevine, Texas-based company plans to raise $325 million, based on its registration filing with the Securities and Exchange Commission. The PC and video game software maker generated $408 million in revenues for the 26-week period ended Aug. 4, compared with $247 million a year ago. Net losses reached $12 million for the period, compared with $9.9 million a year ago. Salomon Smith Barney and UBS Warburg are the underwriters, and the company plans to have its stock trade under the ticker symbol "GSTP."