Bond yields jumped Thursday, erasing the declines stemming from of the Treasury Department’s unusual intervention in the debt market a day earlier.

In early trading, the 10-year Treasury bond yield rose as high as 4.71%, its highest level since Tuesday. The 30-year yield spiked to as high as 5.627%, rising just above the level yields were at when the Treasury Department’s action Wednesday.

As those yields rose, stocks also dropped at the opening bell. The S&P 500 dropped 0.3% and the Nasdaq Composite fell 0.5%. The Dow fell 400 points.

Meanwhile, oil prices accelerated again. U.S. crude oil briefly touched $89 per barrel and international oil benchmark Brent rose to almost $95. The move higher in energy prices came after Trump threatened “economic warfare” on Iran. Gas prices also rose: The national average jumped another two cents from Wednesday to $4.10 per gallon.

The Treasury Department’s surprise announcement on Wednesday effectively meant that it would be a bigger buyer of longer-term bonds. In the immediately aftermath, bonds rallied and yields dropped on that news. However, the impact was short lived, and many market watchers and investors cast doubt on the impact the Treasury’s move would have in the long-run.

On Wednesday afternoon, the Treasury Department revealed that outstanding national debt topped $40 trillion for the first time. Interest payments are on track to surpass Medicare as the government’s greatest expense.

“Absent real fiscal consolidation, we fear the markets will view this action as lacking credibility, meaning this could contribute to higher term premium and yields over time should Treasury become more opportunistic in its approach to debt management and move further away from its ‘regular and predictable’ tenet,” JPMorgan Chase’s global rates team wrote in a note late Wednesday.

The timing of the announcement was “highly unusual,” they added, since it came only two weeks after the Treasury had released its funding plan. “We can find nothing in market functioning that would force” the announcement, JPMorgan’s team added.

Padhraic Garvey, ING’s regional head of research for the Americas, agreed, calling it “quite unexpected.”

Ed Yardeni, president of Yardeni Research, said Wednesday he saw the move by Treasury Secretary Scott Bessent as a signal “that he will do whatever it takes to keep a lid on bond yields.”

Bessent has been intensely focused on bond yields and the knock-on effect they have for consumers since President Donald Trump’s second term began. Consumer borrowing rates move in lockstep with the yield on the 10-year Treasury note.

The average 30-year fixed mortgage rate posted a small drop on Wednesday, according to Mortgage News Daily data. That decline is now likely to be reversed later Thursday.

Asked Wednesday afternoon whether Americans should be concerned about the bond market, Trump told reporters, “No, I don’t think so.”

The Treasury Department did not respond to a request for comment on Thursday morning.

Others warned that the Treasury Department’s move had other consequences.

“Increased Treasury activism — if sustained — could also make the dollar less attractive,” analysts at Evercore ISI wrote. The dollar index, which measures the dollar’s strength against a basket of foreign currencies such as the pound, euro and yen, has fallen nearly 1% since Wednesday morning.

Evercore’s analysts also concurred that “the impact is likely to be short-lived unless fundamentals change.”