Moody’s Ratings downgraded the United States’ debt on Friday, stripping the country of its last perfect credit rating. The move could rattle financial markets and push up interest rates.

Moody’s Ratings slashed the United States’ credit rating down a notch to Aa1 from the highest triple A on Friday, citing the budgetary burden the government faces amid high interest rates.

Financial ratings firm Moody’s Ratings downgraded the U.S. government’s credit ratings Friday, citing its rising debt and interest in a move that underscores a ballooning federal budget deficit, making it the last of the big three firms to downgrade the government’s credit.