South Korea's chip market has become the pressure gauge for the whole AI boom, and it just cracked — bad news for retail investors, retirement savers, and Big Tech's spending story.

• Korean stocks and US tech now move together, because Samsung and SK Hynix build the hardware the AI boom runs on.
• A Chinese state-backed firm is reportedly building its own chipmaking machines, which would break the Western export controls holding China back — Samsung and SK Hynix shares dropped sharply on the news.
• Big Tech is spending faster than AI earns: Alphabet burned billions in one quarter, while Nvidia and Microsoft prop up demand by funding the customers who buy from them.
• Over 320,000 Korean investors — mostly under 35 and trading with borrowed money — had their accounts wiped out, some now owing brokers more than their positions were worth.
• Ordinary 401(k)s and public pensions are quietly exposed, since a handful of AI-heavy companies now make up more than half the S&P 500's value.

Outlook: If AI spending doesn't start paying off, the losses land hardest on retail investors and pension savers who never chose the bet — and unlike the fiber laid in the dot-com era, worn-out data center chips leave nothing useful behind.