KOSPI Tumbles 7% as Chip Rout and China Competition Fears Hit

South Korean stocks cratered Tuesday. The KOSPI dropped 500.47 points, or 7.41%, to 6,253.81, triggering "sidecar" trading curbs on both the mainboard and the junior Kosdaq index that temporarily halted program trading.

The trigger was a two-front assault on the country's dominant semiconductor sector. Memory-chip giant SK Hynix sank 10% after its American depositary receipts hit a record low in New York and slid below their initial U.S. offering price. Samsung Electronics, another heavyweight, fell 9.15%. The two chipmakers together account for more than half the KOSPI's weighting, so the sector-wide rout amplified the damage across the broader market.

Adding to the pressure was news out of China. ChangXin Memory Technologies (CXMT) posted a blockbuster market debut, and reports emerged that a Chinese state-backed firm had begun producing immersion DUV lithography equipment – a technology critical for advanced chip fabrication.

"The market's concern lies less in CXMT's current earnings and more in its potential for accelerated capacity expansion to rival Korean companies and technology development following its IPO," said Kim Seok-hwan, a Seoul-based market analyst at Mirae Asset Securities.

The selloff mirrors a broader global retreat in technology stocks. Japan's Nikkei fell more than 3% in the same session as chip-related names slid across Asia. The KOSPI's level is a low not seen since early 2024.

For investors tracking Korean equities, the key variable is whether the China competition narrative is a short-term headline shock or a structural shift in the memory-chip supply picture. CXMT's post-IPO capital will fund capacity additions; the lithography news suggests Beijing is closing the equipment gap faster than some models assumed. SK Hynix and Samsung both face a market that is now pricing in thinner margins and a faster erosion of their technology lead.

Kim's framing – that the market is pricing CXMT's future capacity, not its current earnings – is the lens through which most Seoul-based analysts are now reading the sector. The next data point will be CXMT's first post-IPO production timeline, which is expected within weeks.