May 5 (Bloomberg) -- General Motors Corp., the world's biggest carmaker, had its debt rating cut to junk by Standard & Poor's, after the company reported its worst quarterly loss in 13 years.

GM had been lowered three times by the ratings company since 2001. GM, with about $300 billion in notes, bonds, loans and asset-backed securities as of Dec. 31, is the biggest company ever cut to junk. The former biggest so-called fallen angel was WorldCom Inc., which had $30 billion of bonds cut to speculative grade on May 10, 2002.

To contact the reporter on this story: Mark Pittman in New York at mpittman@bloomberg.net

Last Updated: May 5, 2005 12:43 EDT