Investors sold stocks and bonds after Moody’s downgraded the U.S. credit rating, potentially complicating negotiations around Republicans’ tax plan.

Investors sold U.S. government bonds and the dollar on Monday amid concerns about the U.S. fiscal picture. Stocks edged higher.

The downgrade follows a change in the outlook on the sovereign in 2023 due to wider fiscal deficit and higher interest payments, and comes as Congress debates tax and spending plans that could deepen the fiscal hole.

Moody’s gave the U.S. a negative outlook—but markets didn’t flinch. This isn’t about default. It’s about trust, and why credibility erosion is the real risk.

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.

After the United States lost its last perfect credit rating on Friday, Republicans and Democrats responded by pointing fingers at each other.