Moody's Investors Service said on Tuesday it would strip the United States of its top-notch rating if a default such as a missed debt payment were to happen and it would not regain the Aaa-status even if the default were resolved.

"An upgrade back to Aaa would be unlikely while the institution of the debt ceiling, and the political environment that gave rise to the missed payment, remained in place," the rating agency's analysts wrote in a report published on Tuesday.