The US Treasury stepped in to prop up the bond market as borrowing costs hit their highest level since 2007 — bad news for anyone with a loan, a mortgage, or a small business.

• The Treasury doubled its buying of long-term government debt to stop yields climbing, an unusual emergency move.
• Fewer buyers want US debt, so the government has to pay more to borrow — and interest now eats 14% of federal spending.
• US debt just hit $40 trillion, and central banks around the world are shifting into gold instead of Treasuries.
• The Fed is holding rates steady and worries high inflation from the Iran war is becoming permanent.
• Big tech can shrug off costly borrowing; small businesses, homebuyers, and car buyers cannot.

Outlook: Rates look set to stay high for years, raising the risk of a debt spiral where borrowing costs feed on themselves.