Continued worries about the U.S. fiscal outlook triggered another selloff in long-dated U.S. government debt as of Wednesday morning, pushing the yield on the 30-year bond back above 5% for the second time this week in what turned out to be a problematic development for stocks.

The downgrade of the country’s credit rating by Moody’s hurt investor confidence. So has trade policy, and ballooning federal debt.

Stocks turned lower Wednesday after a disappointing Treasury bond auction accelerated a selloff in the debt market. The Dow Jones Industrial Average dropped about 600 points, or 1.5%, leading indexes lower in afternoon trading.

Financial markets are once again focused on Washington, D.C., but taxes, not tariffs, are driving recent price action.

The Dow closed lower by 817 points, or 1.91%. The broader S&P 500 slid 1.61% and the tech-heavy Nasdaq Composite fell 1.41%. The three major indexes each posted their worst day in one month. Stocks moved sharply lower and bonds sold off after a 1 p.