SK Hynix falls 11%, Samsung 9.5% and Advantest 15% in a chip rout Wall Street barely felt

The sell-off in artificial intelligence hardware stocks hit hardest in Asia on Thursday. SK Hynix, the South Korean memory maker, closed down 11.1% at 1,262,000 won, and Samsung Electronics fell 9.5% to 210,000 won, according to Yahoo Finance price data. In Tokyo, chip-testing equipment maker Advantest dropped 15.0%. CNBC reported that 20 of the most valuable global AI and semiconductor stocks have lost more than $1 trillion in value this week.

Source: Yahoo Finance daily closes. One month runs from September 15 for Asian listings and September 16 for U.S. listings. CNBC's intraday figures for some of these names differ slightly from the closing numbers above.

The same sell-off, two very different sizes

The table shows how uneven the damage was. TSMC, the world's largest contract chipmaker, fell only 2%. SK Hynix is now down a quarter in a month, while Advantest, which fell the most on the day, is still up 13.9% over the same stretch. That makes Thursday look less like a collapse in one story and more like a sharp repricing of the names that had run furthest on AI spending.

In the United States the pain was narrower. Nvidia fell 1.8% and AMD 1.5%, and Micron rose 1.9%. Dell dropped 6.8% and is down 19.2% from last Friday's close. Our market close report shows the Nasdaq Composite finished essentially flat, with industrials and health care taking the money that left tech.

What CNBC says is driving it

CNBC pointed to three pressures. The first is the cost of money: with Treasury yields above 5% and a Fed meeting on October 28, investors worry that higher borrowing costs will squeeze the capital spending needed to build AI data centers. Broadcom's Hock Tan and Intel's chief executive both warned on Monday, per CNBC, that financing could become a major headwind. Tan said it could be a bigger challenge than chip or electricity shortages.

The second is supply. CNBC said worries that the memory market could be oversupplied as early as 2029 are weighing on sentiment after China's ChangXin Memory Technologies announced what it called a breakthrough in memory architecture over the weekend. That would explain why Korean memory makers fell furthest, though CNBC presented it as one factor among several.

The third is credit. Our CoreWeave report covers the swap spread above 1,000 basis points that S&P Global Market Intelligence calls distress. CNBC reported that neocloud stocks recovered after Nvidia chief executive Jensen Huang told Bloomberg he saw no need to backstop CoreWeave and that its cost of capital is decreasing.

Who this reaches beyond the chip names

For a business owner outside technology, the link is financing cost, not chip prices. The 10-year Treasury closed Thursday at 5.10% per the Treasury's par yield curve, and that is the level the AI sell-off is being argued over. Whether it reaches ordinary borrowers depends on how long yields stay there, and we have not seen any verified sign yet of tighter credit or higher equipment prices outside the AI complex.

What we could not confirm

We did not find a company-specific announcement behind SK Hynix's or Advantest's drop on Thursday; the explanations above are CNBC's reading of sentiment, not disclosed news. We also could not independently verify the $1 trillion figure, which is CNBC's tally across 20 stocks.

Sources: CNBC; Yahoo Finance; Chronicle reports linked above. Prices are closing levels for Thursday, October 15, 2026. This is market information, not investment advice.