Treasury yields are already blowing up the CBO’s long-term forecasts, and experts who previously downplayed U.S. debt fears are now starting to worry

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The 10-year Treasury yield topped 5% this past week, hitting the highest level since 2007 and blowing way past forecasts for borrowing costs over the next decade.

According to the Congressional Budget Office’s most recent long-term outlook issued in February—before the Iran war spiked oil prices and inflation views—the benchmark yield was seen at 4.1% this year and 4.2% in 2027. The 10-year yield was expected to hover around 4.3% from 2028 to 2031, then tick up to 4.4% from 2032 to 2036.