Moody’s Investors Service downgraded the U.S. sovereign credit rating from Aaa to Aa1, marking the first time all three major credit rating agencies—Moody’s, S&P, and Fitch—have rated U.S. debt below the top tier.

All three major U.S. stock market indexes rose Monday afternoon, following an earlier selloff sparked by long-dated Treasury yields surpassing the 5% mark after the financial ratings agency Moody’s downgraded the U.S. government’s credit rating late last week, citing rising debt and interest payment ratios.