South Korean stocks plunged right from the open today. The KOSPI fell more than 6–7% at one point, triggering a sell-sidecar (a pause in program trading). It dropped to around 5,600 during the session, its lowest level since late July, and has now fallen for seven consecutive trading days.
Samsung Electronics $SAMSUNG , SK hynix $SKHYNIX and other heavyweight stocks plunged more than 6–10% right from the open.
Related U.S. stocks and instruments also weakened overnight:
$EWY (South Korea ETF) fell sharply overnight, directly reflecting expectations for the KOSPI. MU (Micron), SNDK (SanDisk, NAND flash memory) and other stocks also fell significantly overnight, moving closely in tandem with South Korea’s two memory-chip giants.
Key factors:
1. U.S. inflation data came in hotter than expected: September CPI rose 0.6% month over month and 3.7% year over year, above expectations. Markets are again concerned that Fed rate cuts could be delayed—or that rates could even be raised again—putting pressure on valuations of growth and technology stocks.
2. Concerns over AI investment returns and financing continue to build: OpenAI revenue forecasts had already been revised downward, and executives at Broadcom and other companies had warned about capital constraints. These concerns, along with worries about debt and financing at AI cloud companies such as CoreWeave, have led the market to question whether “AI capital spending can continue to deliver.” South Korea’s market is heavily concentrated in Samsung and SK hynix, making it particularly sensitive to this sentiment.
3. Competitive concerns are adding to the pressure: Progress by China’s CXMT and others on new DRAM architectures continues to weigh on sentiment. The market is concerned about intensifying competition on the supply side and the risk that the pricing cycle may have peaked. Foreign investors have been net sellers for several consecutive days, with selling on a single day previously reaching the scale of trillions of Korean won. The South Korean market has little buying support to cushion the decline.
4. Technical factors and sentiment are reinforcing each other: Daily charts show that the KOSPI, EWY, MU and SNDK have all pulled back significantly from their highs and fallen below several key moving averages. The short-term trend has weakened, and selling pressure has been substantial.
In the short term, if expectations for U.S. interest rates continue to rise and foreign outflows persist, the index may continue to test lower support levels.
In the medium term, the outlook depends on whether HBM/DRAM can sustain strong demand and whether capital spending on AI infrastructure genuinely slows.
The decline has already been substantial. If clear catalysts emerge—such as signs that AI spending remains strong or that inflation is easing—a technical rebound is possible. However, it would be unwise to rush into buying the dip before the downtrend shows signs of weakening.
(The above is solely my personal analysis and does not constitute investment advice. Markets involve risk; investment decisions should be made independently.)
Samsung Electronics $SAMSUNG , SK hynix $SKHYNIX and other heavyweight stocks plunged more than 6–10% right from the open.
Related U.S. stocks and instruments also weakened overnight:
$EWY (South Korea ETF) fell sharply overnight, directly reflecting expectations for the KOSPI. MU (Micron), SNDK (SanDisk, NAND flash memory) and other stocks also fell significantly overnight, moving closely in tandem with South Korea’s two memory-chip giants.
Key factors:
1. U.S. inflation data came in hotter than expected: September CPI rose 0.6% month over month and 3.7% year over year, above expectations. Markets are again concerned that Fed rate cuts could be delayed—or that rates could even be raised again—putting pressure on valuations of growth and technology stocks.
2. Concerns over AI investment returns and financing continue to build: OpenAI revenue forecasts had already been revised downward, and executives at Broadcom and other companies had warned about capital constraints. These concerns, along with worries about debt and financing at AI cloud companies such as CoreWeave, have led the market to question whether “AI capital spending can continue to deliver.” South Korea’s market is heavily concentrated in Samsung and SK hynix, making it particularly sensitive to this sentiment.
3. Competitive concerns are adding to the pressure: Progress by China’s CXMT and others on new DRAM architectures continues to weigh on sentiment. The market is concerned about intensifying competition on the supply side and the risk that the pricing cycle may have peaked. Foreign investors have been net sellers for several consecutive days, with selling on a single day previously reaching the scale of trillions of Korean won. The South Korean market has little buying support to cushion the decline.
4. Technical factors and sentiment are reinforcing each other: Daily charts show that the KOSPI, EWY, MU and SNDK have all pulled back significantly from their highs and fallen below several key moving averages. The short-term trend has weakened, and selling pressure has been substantial.
In the short term, if expectations for U.S. interest rates continue to rise and foreign outflows persist, the index may continue to test lower support levels.
In the medium term, the outlook depends on whether HBM/DRAM can sustain strong demand and whether capital spending on AI infrastructure genuinely slows.
The decline has already been substantial. If clear catalysts emerge—such as signs that AI spending remains strong or that inflation is easing—a technical rebound is possible. However, it would be unwise to rush into buying the dip before the downtrend shows signs of weakening.
(The above is solely my personal analysis and does not constitute investment advice. Markets involve risk; investment decisions should be made independently.)