Standard and Poor's on Monday affirmed Japan's sovereign-debt rating at AA- while maintaining a negative outlook and warning that a downgrade is likely if medium-term growth prospects weaken.
The ranking is "supported by the country's ample net external asset position, relatively strong financial system and diversified economy," S&P said in a statement. It cited the yen's role as a "key international reserve currency."
Prime Minister Yoshihiko Noda is struggling to tame the world's biggest public debt burden while supporting an economy that was hurt by last year's earthquake and tsunami and shrank an annualized 2.3 percent in the fourth quarter. He's yet to secure lawmakers' support for a sales tax increase intended to put the nation on a stronger financial footing.