The downgrade of the U.S. sovereign credit rating Friday will likely mean higher borrowing costs on mortgages.

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

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.

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

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.

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