South Korea’s KOSPI plunged more than 6% intraday on the 13th, surrendering the 6,000 level for the first time in over two months. Foreign investors dumped nearly 2 trillion won (approximately $1.5 billion) in net selling as top-cap semiconductor stocks including Samsung Electronics and SK Hynix tumbled in tandem. The rapid widening of losses triggered a sell-side circuit breaker on the main KOSPI board, temporarily halting program sell orders.

According to the Korea Exchange, as of 10:43 a.m., the KOSPI stood at 5,969.68, down 414.56 points (6.49%) from the previous session. The index last traded below the 6,000 mark on July 31, roughly two and a half months ago. The index opened down 198.16 points (3.10%) and extended losses throughout the morning, breaking through the 6,100 level and then the 6,000 level in succession.

As the selloff accelerated, a sell-side circuit breaker was triggered on the main board at 9:47:58 a.m. At that moment, KOSPI 200 futures were trading at 955.02, down 51.20 points (5.08%) from the base price of 1,006.22. The sell-side circuit breaker activates when KOSPI 200 futures fall 5% or more below the base price for at least one minute, suspending program sell orders for five minutes. This marked the first circuit breaker activation on the main board since August 20, and the first sell-side circuit breaker specifically since August 19 — roughly two months ago.

Foreigners Sell Nearly 2 Trillion Won; Semiconductor Duo Plunge

The day’s decline was driven by heavy foreign selling. In the first hour and a half of trading, foreign investors net sold 1.9823 trillion won (approximately $1.5 billion) worth of shares on the main KOSPI board. They also held a net short position of 191.9 billion won (approximately $143.5 million) in KOSPI 200 futures. Retail and institutional investors absorbed the selling pressure with net purchases of 1.4271 trillion won (approximately $1.1 billion) and 518.5 billion won (approximately $387.8 million), respectively, but it was not enough to stem the decline.

Decliners overwhelmed advancers. Among KOSPI-listed companies, 828 stocks fell while only 71 rose.

The semiconductor “duo” suffered particularly steep losses. Samsung Electronics traded at 233,000 won (approximately $170), down 17,500 won (6.99%) from the previous session. SK Hynix fell even harder, dropping 142,000 won (8.85%) to 1.463 million won (approximately $1,100). With most large-cap stocks in the red, SK Square (-11.48%), Samsung Electro-Mechanics (-8.27%), Hyundai Motor (-5.78%), Samsung Life Insurance (-5.98%), and Samsung SDI (-7.66%) also posted sharp declines.

At the same time, the KOSDAQ index was down 37.39 points (4.40%) at 811.80. The simultaneous plunge in both major indices signaled broad-based selling pressure across South Korea’s equity market.

CXMT Technology Progress Weighs on Investor Sentiment

The direct catalyst for the semiconductor selloff was news of technological progress by Chinese memory chipmaker ChangXin Memory Technologies (CXMT). CXMT’s announcement of advancements in DRAM technology development raised concerns about the competitiveness of South Korean semiconductor companies. In particular, reports that CXMT plans to unveil server memory products incorporating new technology within the year heightened market wariness.

Market observers interpreted the selloff as reflecting fears that if Chinese players’ technology catch-up accelerates, supply competition in the global memory semiconductor market could intensify further, dampening investor sentiment.

Goldman Sachs Raises ASMPT Target to HK$183

Separately, Goldman Sachs raised its target price on ASMPT (0522.HK), maintaining a positive outlook on the company’s exposure to advanced packaging applications. The investment bank expects ASMPT to benefit from technology migration to finer pitches and expanding applications in GPU, ASIC, and HBM.

Goldman Sachs projects ASMPT’s Q3 and Q4 revenue to reach HK$5.172 billion (approximately $659.1 million) and HK$5.325 billion (approximately $678.6 million), up 5% and 3% quarter-over-quarter respectively, driven by sustained AI server demand benefiting TCB (thermocompression bonding), photonics equipment, and SMT equipment.

Specifically, TCB demand is expected to be driven by advanced logic and HBM applications, while pluggable optical transceivers should drive near-term growth in photonics equipment. Hybrid bonding and CPO (co-packaged optics) were identified as long-term opportunity factors.

Goldman Sachs raised its 2026–2028 net profit estimates for ASMPT by 4%, 6%, and 12%, respectively, reflecting lower operating expense ratio assumptions based on a positive outlook for operational efficiency improvements. Applying a 2030 discounted price-to-earnings (PER) methodology, the bank raised its 12-month target price by 3% from HK$177 (approximately $23) to HK$183 (approximately $23). The target multiple of 24.9x 2030 estimated PER was maintained, and the Neutral rating was retained on the view that current valuation is appropriate.