Factbox: The fallen AAAngels of sovereign ratings

(Reuters) - If the United States' credit rating is cut from the unblemished AAA status, the world's largest economy would join a group of nations -- Ireland, Japan and Spain -- that lost the coveted status.

A downgrade by one or more of the big three credit rating agencies -- Standard & Poor's, Moody's Investors Service and Fitch Ratings -- remains a distinct possibility even as lawmakers struggle to reach an agreement on deficit reduction and a raising of the current $14.3 trillion statutory debt limit.

In the case for each fallen angel, the immediate reaction by investors was to sell benchmark 10-year debt; however, the magnitude of moves were relatively minor.