South Korea's Kospi triggered a market-wide circuit breaker on Friday, halting trading in stocks and derivatives for 20 minutes at 9:03 a.m. local time as an AI chip selloff that started on Wall Street hit Samsung Electronics and SK Hynix. The index fell as much as 8.7% to an intraday low of 4,911.28 before closing down 324.15 points, or 6.02%, at 5,059.65.
Kospi opened at 5,263.26 at 9:01 a.m., down 120.54 points, according to Yonhap. That extended a 5.28% drop on Thursday, when the index closed at 5,383.80. The Kosdaq finished Friday 5% lower. Several outlets counted the halt as the 11th of 2026, while Yonhap counted it as the tenth.
Samsung Electronics and SK Hynix together account for more than half of the Kospi's weight, which made the two memory makers the center of the move. SK Hynix slid more than 10% and Samsung fell 6.35% by the close. At the moment of the 9:03 a.m. halt, the pair were about 225.6 trillion won, roughly $166 billion, below their combined value at Thursday's close.
Key facts
- 01Kospi tripped a 20-minute market-wide circuit breaker at 9:03 a.m. local time on Friday, November 6.
- 02The index hit an intraday low of 4,911.28, down 8.7%, then closed down 6.02% at 5,059.65.
- 03SK Hynix slid more than 10% and Samsung Electronics fell 6.35%; the pair make up more than half of Kospi's weight.
- 04On Thursday the Philadelphia Semiconductor Index fell 12.2%, Nvidia lost 9.3% and AMD dropped 17.3%.
- 05About $3 trillion was wiped off the market value of S&P 500 companies in Thursday's US session.
Both companies are the dominant suppliers of high-bandwidth memory for Nvidia's AI accelerators, so their shares tend to track the US chip trade. Foreign funds sold both stocks heavily at the open.
The selling began in New York on Thursday. The Nasdaq Composite fell 5.5%, the S&P 500 dropped 4.4% and the Philadelphia Semiconductor Index lost 12.2%, its largest single-day decline since April 2025. About $3 trillion was erased from the market value of S&P 500 companies.
Nvidia fell 9.3% in the US session, wiping out its gains for the year, and Advanced Micro Devices dropped 17.3%. A weak earnings outlook from Qualcomm added to the pressure on chip stocks.
Investors tied the rout to Democrats' gains in the November 3 US midterm elections, which put spending by US cloud companies on AI and data center construction under closer scrutiny. Expensive valuations, borrowing costs and doubts about returns on AI investment also weighed on the sector.
Wall Street strategists had flagged the risk before the vote. Bank of America's Michael Hartnett warned that a full Democratic sweep could trigger a 10% slide in US stocks, and Citigroup's Scott Chronert said a sweep would hand key committees to Democrats and called it a marginal negative for the AI trade.
The selloff spread across the region. Japan's Nikkei 225 fell more than 6% in early trading, with Advantest, Renesas Electronics and SoftBank among the sharp decliners, and Taiwan's tech-heavy market also dropped steeply.
South Korean officials convened an emergency meeting to review market conditions, and domestic investors helped trim the Kospi's losses after the heavy foreign selling. Analysts said the drop reflected sentiment rather than a collapse in demand for AI chips.
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