Mark Shapiro, the New York-based company's chief executive officer, says the move won't affect the operation of its 20 theme parks in the US, Mexico and Canada.

Six Flags says it actually had a great year in 2008. It saw 25 million visitors to its parks and posted record revenues. But executives are trying to lighten a US$2.4 billion debt load that they say is unsustainable.

Saturday's bankruptcy filing came after an earlier plan to negotiate an out-of-court deal with creditors failed.

Six Flags shares have traded below US$1 since September. They closed at 26 cents on Friday. -- AP