Samsung Electronics, SK Hynix Fall as Post-Holiday Flows Diverge

What the Declines in Samsung Electronics and SK Hynix Signal

The early-session declines in Samsung Electronics and SK Hynix suggest that overseas market volatility accumulated during the holiday and the day’s supply-demand (order flow) initially outweighed the semiconductor sector’s long-term narrative. On Sept. 28, 2026, the first trading day after the Chuseok holiday, concentrated selling by foreign investors and institutional investors in the KOSPI electrical and electronics industry sector left both stocks in negative territory. Investors now need to distinguish between changes in the underlying value of the semiconductor businesses and a price adjustment that was reflected all at once when the market reopened.

According to Yonhap News Agency’s market report, Samsung Electronics was trading at 282,000 won as of 9:12 a.m., down 1.23% from the previous session, while SK Hynix was down 2.69% at 1,812,000 won. Closing prices and final price change rates were not yet available. Rather than declaring this a trend reversal, investors should first assess the direction of intraday supply-demand (order flow) and changes in the scale of the declines.

First Session to Reflect U.S. Index Declines During the Holiday

Price discovery was suspended in the Korean market during the holiday, so changes in the U.S. market were reflected only after trading resumed. Price discovery is the process through which new information is incorporated into share prices via buy and sell orders. Compared with the Korean market’s Sept. 22, 2026 reference date, the Dow Jones Industrial Average ended last week down 35.07 points, or 0.07%, at 51,828.62.

On the same basis, the Standard & Poor’s (S&P) 500 Index fell 21.23 points, or 0.27%, while the Nasdaq lost 175.56 points, or 0.64%. The Philadelphia Semiconductor Index, which is closely tied to the chip industry, also declined 20.89 points, or 0.16%. Weakness across major overseas indexes did not provide a favorable opening backdrop for Korean semiconductor stocks, but the respective index declines alone cannot explain the difference between the losses in Samsung Electronics and SK Hynix.

Iran said it had presented the United States with a plan calling for an end to hostilities and the reopening of the Strait of Hormuz. This indicates that the uncertainty that developed during the holiday was not fixed. However, the available information does not provide sufficient grounds to conclude that geopolitical developments were the definitive cause of the two stocks’ declines.

SK Hynix Fell More Than Samsung Electronics in Early Trading

Samsung Electronics opened down 0.35% at 284,500 won, subsequently recovered to the previous session’s closing price, and then extended its decline to 1.23% by 9:12 a.m. SK Hynix dropped as low as 1,810,000 won, or -2.79%, shortly after the open before trimming part of its loss to 1,812,000 won and -2.69% at the same time. Their intraday paths show that the pace of incoming orders and the intensity of selling pressure differed even within the same industry sector.

In the KOSPI market as of the time of writing, foreign investors posted net sales of 82.6 billion won and institutional investors sold a net 83.3 billion won, while retail investors recorded net purchases of 111.9 billion won. Within the KOSPI electrical and electronics industry sector, foreign and institutional investors posted net sales of 98.6 billion won and 85.4 billion won, respectively, while retail investors recorded net purchases of 138 billion won. The clearer selling pressure in industry-sector supply-demand (order flow) than in the overall market coincided with weakness in the two semiconductor stocks.

Samsung Electronics and SK Hynix conducted share buybacks, while other corporate entities recorded net purchases of 46.1 billion won as of the time of writing. It would be difficult to conclude that this buying fully absorbed the shares sold by foreign and institutional investors. Continued share-buyback-related purchases could help support prices intraday, but a shift by institutional investors to net buying would provide clearer grounds for a recovery.

What to Check to Distinguish a Rebound From Further Weakness

• Foreign-investor supply-demand (order flow): A reduction in the 98.6 billion won of net selling recorded in the KOSPI electrical and electronics industry sector would indicate whether the pressure seen at the open is easing. If selling expands, a recovery from the semiconductor stocks’ declines may be delayed.
• Institutional direction: If the industry sector’s 85.4 billion won of institutional net selling persists, the 138 billion won of net purchases by retail investors alone may have limited power to reverse prices. The supply-demand (order flow) picture would change if institutional investors shift to net buying.
• Intraday path of each stock: Samsung Electronics extended its decline after the open, while SK Hynix partially recovered from its low shortly after trading began. Rather than focusing only on their shared direction, investors should separately monitor whether each stock recovers from its decline or falls further.
• Limits of the assessment: All current figures are from early trading or the time the article was written. Until closing prices and final net trading figures by investor type are available, it is not possible to distinguish a short-term supply-demand (order flow) shock from sustained weakness.

One reason for urgency is that declines in major U.S. indexes during the holiday were reflected in Korean prices, while one reason to wait is that early-session data cannot reveal final supply-demand (order flow) or closing prices. The next assessment should be based not on a vague semiconductor narrative but on the closing price change rates of Samsung Electronics and SK Hynix, final net trading by foreign and institutional investors in the electrical and electronics industry sector, and whether purchases by other corporate entities persist.

This article was automatically summarized and analyzed from the original news report. View original article (Yonhap News Agency Markets)