Bond yields are jumping across the US, Japan, Europe and Asia at once, and that is bad for stocks, tech companies and anyone borrowing money.

• US government bond yields pushed past 4.8% as heavy government borrowing collides with high inflation, and stocks fell across the board.
• The Fed is stuck: raising rates would blow up the cost of refinancing trillions in maturing debt, but doing nothing looks like giving up on inflation.
• The Iran conflict is making it worse — oil is back near $95 a barrel, tankers near Hormuz have reportedly been hit, and no insurer wants that risk.
• Tech is falling hardest because the huge AI data center buildout is funded by borrowing, and those loans get much more expensive as yields rise.
• Japan and South Korea sold off sharply, and cutting trade with Canada and China would leave fewer dollars abroad to buy US debt.

Outlook: If yields keep climbing together worldwide, the AI spending boom stalls and stock markets fall further.