20101027 french students protest against pension reforms ah 18
PARIS - OCTOBER 26: French university students and striking workers attend a demonstration over pension reforms near the French Senate October 26, 2010 in Paris, France. - 

STEVE CHIOTAKIS: Investors and economists are now asking who's next? Which country do investors and economists think is headed for the same fate as the United States? A lot of folks think France's rating will be cut next.

The BBC's Rob Young reports.

ROB YOUNG: France may be next on the downgrade hit list. Some analysts say French debt levels are as unsustainable as America's.

Neil Mackinnon is an economist at VTB Capital, an investment bank, in London.

Neil Mackinnon: The debt level of France is highest among all of the Eurozone AAA rated countries, and its government budget deficit is the second-highest. In addition, we know that French banks have the most exposure to Greek debt, Irish debt, Portuguese debt, within the Eurozone.

If Greece, Ireland and Portugal struggle to repay their debs, France could be in trouble. And that's what has credit rating agencies worried. But it's not just France who risks the loss of its top-notch credit rating in Europe. Belgium and even the U.K. are seen as vulnerable to a downgrade.

The U.S. -- as the world's biggest economy -- may be able to weather the storm of a debt downgrade. However, smaller countries may not.

I'm the BBC's Rob Young, for Marketplace.