#KOSPIPlunges9%

South Korea's equity market just delivered one of its sharpest shock sessions in months.

KOSPI plunged 9% on July 28, breaking below 6,200 for the first time since April. The Korea Exchange activated both the sell-side sidecar and market-wide circuit breaker, temporarily halting program sell orders as panic spread across the market.

The semiconductor sector led the decline:

SK Hynix: -12%+

Samsung Electronics: -10%+

The pressure followed a weak U.S. chip session, where the Philadelphia Semiconductor Index lost more than 2%, SanDisk fell 11%, and Nvidia dropped around 5%.

The catalyst was ChangXin Memory Technologies (CXMT). Its blockbuster Shanghai debut intensified concerns that China's emerging DRAM champion could challenge the long-standing memory chip oligopoly dominated by Samsung Electronics, SK Hynix, and Micron.

Several bearish themes collided at once:

Fears of oversupply in the memory market

Expectations that DRAM pricing may have peaked

Questions about the sustainability of AI-driven semiconductor demand

The prospect of a powerful new competitor scaling production

While a single IPO cannot reshape the industry overnight, the market is rapidly repricing the possibility that future memory margins could face greater competitive pressure than previously expected.

For semiconductor investors, the focus has shifted from peak earnings to the durability of the next cycle.