Moody's Ratings downgraded U.S. debt, becoming the last of the three major credit rating agencies to move in that direction.

Moody’s lowered the U.S. credit score to Aa1 from Aaa on Friday, joining Fitch Ratings and S&P Global Ratings in grading the world’s biggest economy below the top, triple-A position. The one-notch cut comes more than a year after Moody’s changed its outlook on the U.S. rating to negative. The credit assessor now has a stable outlook.