A big selloff is hitting SpaceX and the broader market, which is bad news for investors — especially anyone using borrowed money.

• SpaceX has lost over $1.2 trillion in value since its IPO, falling in most recent trading sessions.
• The drop is spreading globally — South Korea's market plunged 8% and had to freeze trading to stop the selling.
• Fear is growing that AI spending is a bubble built on debt and "circular financing," where Nvidia funds the same companies buying its chips.
• Nvidia is working on $750 billion in new AI deals, but investors now want proof of real demand, not just growing revenue.
• Warnings are piling up that this looks like the dot-com bust — Jim Cramer says to dump any data-center stock bought with borrowed money.

Outlook: If big tech pulls back on AI spending or the debt stops flowing, the selloff could deepen fast.