KOSPI Falls 5.5% as Memory-Chip Selloff Deepens: What Happened and What's Accurate

South Korea's main stock index fell sharply on Tuesday, October 13. The KOSPI closed at 6,035.35, down 348.89 points, or 5.46%. It was the second large decline in a row: on Monday the index had closed down 3.65% at 6,384.24.

Intraday low versus close#

Many headlines reported a drop of more than 7%. That was the move during the session, not the final result. The index opened 3.10% lower at 6,186.08 and fell below 6,000 in the morning, according to the Seoul Economic Daily. The Associated Press reported the index down 7.4% at 5,914.35 at one point, its lowest level since late July. Buyers then recovered part of the decline before the close.

Exchange pauses program selling#

At 9:47 a.m. local time, KOSPI 200 futures had fallen 5.08%. The Korea Exchange then triggered a sell-side "sidecar," which briefly holds program sell orders. It was the first sell-side sidecar on the KOSPI since August 19. A sidecar is a short cooling-off measure. It is not a full market halt, and trading continued.

Memory chipmakers led the decline#

The selloff centered on Samsung Electronics and SK hynix, the two largest memory chipmakers in the index. By mid-morning, Samsung was down 6.79% and SK hynix 8.54%. Later in the session, the AP reported declines of 7.7% and 8.8%. Closing prices for the two stocks had not been confirmed when this article was published.

Reports linked the move to China's ChangXin Memory Technologies (CXMT). The company said it would introduce next-generation server DRAM products this year. Investors worried that more Chinese supply could increase competition for Samsung, SK hynix and Micron.

Foreign investors were the main sellers. By 10:40 a.m., they had net sold 1.81 trillion won of shares on the main board. Individual investors had net bought 1.05 trillion won, and institutions 598.7 billion won.

How far the index has fallen#

The AP reported that the KOSPI topped 9,000 in June, its record high. Tuesday's close leaves it roughly a third below that level. The smaller KOSDAQ index fell 4.44% to 811.49 in morning trading.

Other Asian markets also fell, though less. Japan's Nikkei 225 dropped 2.5% and Taiwan's Taiex 1.9%. Hong Kong's Hang Seng and the Shanghai Composite each lost about 1%. Oil prices remain a separate concern: Brent crude was about $105 a barrel on Tuesday, up from about $72 in late February.

Fact-check notes#

• "KOSPI crashed more than 7% today" — partly accurate. The index was down more than 7% during trading but closed down 5.46%.
• "Trading was halted" — not accurate. The exchange paused only program sell orders, through the sidecar. A full circuit-breaker halt was not reported.
• "China caused the crash" — overstated. Reports cite CXMT's DRAM plans as the main trigger. Foreign selling, high oil prices and doubts about AI-related spending also played a part, and the index had already fallen 3.65% the day before.

What to watch next#

For U.S. investors, the more direct link is to memory and semiconductor stocks such as MU. One session does not show whether competition will lower memory prices or company profits. Earnings reports and memory pricing over the coming quarters will answer that more clearly than a single day's index move.

Published October 13, 2026. Figures come from the cited reports. Intraday figures are labeled with their time where known. Informational reporting, not investment advice.