US government borrowing costs jumped to their highest level since 2007, and the Treasury's attempt to push them back down lasted less than a day — bad news for anyone with a mortgage, a business loan, or money in stocks.

• The yield on the 30-year Treasury bond topped 5.3%, meaning investors now demand much more to lend to the US government.
• Treasury Secretary Scott Bessent spent $4 billion buying back government bonds to force yields down; they bounced right back and the Dow fell 700 points.
• Investors want a bigger payout because they no longer trust the US to handle a $40 trillion debt that now costs over $1 trillion a year in interest alone.
• The Iran conflict is making it worse — the Strait of Hormuz is closed, Houthi attacks continue in the Red Sea, and oil neared $90 a barrel, keeping inflation fears alive.
• Bessent said on TV he doesn't understand why oil prices spiked, which spooked markets further and undercut confidence in the administration.

Outlook: Treasury yields look set to stay high, pushing up borrowing costs across the economy unless Washington deals with the deficit or the Iran conflict cools.