On Oct. 15, Samsung Electronics fell 9.48% and SK hynix fell 11.06%. That was the day circuit breakers (a device that briefly halts trading when an index stays down 8% or more from the previous day for one minute) hit both the KOSPI and the KOSDAQ. The next day, Oct. 16, the KOSPI rebounded 2.05%, but Samsung Electronics rose only 2.62% and SK hynix only 0.79%. The gains differed by more than 3 times.
The common take is "the two chip leaders fell together, so they will rebound together." But that same day, foreign investors traded the two stocks in opposite directions.
On the 16th, foreign investors were net buyers of Samsung Electronics for the first time in 13 trading days, and net sellers of SK hynix for the 16th trading day in a row. No analysis says this caused the price gap, though. News reports give these reasons for the rebound: bargain buying after a big drop, lower U.S. Treasury yields, and improved sentiment on AI investment.
- How far did the two stocks fall together?
From Oct. 6 to Oct. 15, over 7 trading days, Samsung Electronics fell 23.9% and SK hynix fell 31.5%. Both dropped a lot, but SK hynix fell further.
If you held KRW 1 million of each, you would be left with about KRW 760,000 in Samsung Electronics and about KRW 680,000 in SK hynix. To get back to the starting price, Samsung Electronics would need to rise about 31% and SK hynix about 46% (a hypothetical calculation). Put simply, the stock that fell more is farther from its old price even if it rises by the same amount.
- How did the two stocks move on the rebound day?
They differed from the start. On the 16th, Samsung Electronics opened up 2.38%, while SK hynix turned lower after the market opened and fell as low as KRW 1,247,000 (-1.19%).
Both stocks gave back part of their gains ahead of the close. Samsung Electronics rose as much as 5.95% at one point but finished at 2.62%. Closing prices were KRW 215,500 for Samsung Electronics (+2.62%) and KRW 1,272,000 for SK hynix (+0.79%).
- How did foreign investors buy and sell the two stocks that day?
On the 16th, foreign investors were net buyers of Samsung Electronics by KRW 181.9 billion. It was the first day in 13 trading days, since Sept. 23, that they bought more than they sold. The same day they were net sellers of SK hynix by KRW 73 billion, the 16th trading day in a row, since Sept. 21, that they sold more than they bought.
SK hynix net selling fell sharply from KRW 1.1846 trillion the day before by Capital Market News's count (Segye Ilbo reported KRW 1.1112 trillion) to KRW 73 billion. It shrank, but it was still net selling. Think of a flea market: SK hynix had fewer items on offer, but sellers still outnumbered buyers, while for Samsung Electronics buyers now outnumbered sellers. Unlike a flea market, though, individuals, institutions and companies also trade stocks alongside foreign investors.
There was a gap even before the rebound. By Korea Exchange figures (reported by Financial News), from Oct. 1 to 15 foreign investors net sold KRW 9.36 trillion of SK hynix and KRW 4.9278 trillion of Samsung Electronics on the main KOSPI market. By Financial News's count, that is nearly twice as much SK hynix.
- While foreign investors sold SK hynix, who bought?
At its August board meeting, SK hynix decided on a share buyback: it would spend about KRW 40 trillion buying 24.07 million of its own shares on the market and cancelling them. The original deadline was Nov. 19.
From Aug. 21 to Oct. 12, foreign investors net sold KRW 20.9691 trillion of SK hynix. Over the same period, "other corporations" (the line in exchange statistics that includes companies' own share buybacks) net bought KRW 35.3658 trillion. The two figures cannot be matched one-to-one, but while foreign investors were selling, net buying was large on the side that includes the buyback.
As of Oct. 12, that buyback was reported to have bought 20.45 million of the 24.07 million shares. The remaining 3.62 million shares or so were expected to be finished within 9 trading days at around 400,000 shares a day. This is as reported on Oct. 14, and we could not confirm whether it has ended since. Samsung Electronics finished its buyback on Oct. 6.
- What is the crossroads once the buyback ends?
Financial News (News1) said the key is whether a new buyer will appear to take the place of "other corporations" after the buyback ends. Yuanta Securities analyst Lee Jae-won said that for foreign investor demand to recover, "calm over AI credit risk and restored confidence in chip earnings forecasts must come first," and that the firming up of shareholder return plans at the end of October and whether they are actually carried out "will decide the character of the rebound."
SK hynix has said it will announce the size and form of additional shareholder returns with its third-quarter results. Whether that announcement fills the gap left after the buyback is the next crossroads.
- BITPRESS Insight
The two stocks that fell together did not rise by the same amount on the rebound day. Foreign trading that day also differed: Samsung Electronics saw net buying, while SK hynix saw net selling that had only shrunk. Whether this caused the price gap has not been confirmed.
For SK hynix, while foreign net selling continued, net buying by "other corporations," which includes the buyback, was large, and that buyback was reported to have filled most of its plan as of Oct. 12. That is why analysts say the key is who buys once it ends.
In the reporter's view, if you hold both stocks, it is worth looking at not just how much each rose on a rebound day, but whether foreign investors were selling that stock less or buying it again. Selling less and turning to net buying are not the same thing.
Sources
https://www.jabon.co.kr/news/articleView.html?idxno=7746
https://www.getnews.co.kr/news/articleView.html?idxno=883824
https://www.wowtv.co.kr/NewsCenter/News/Read?articleId=A202610160142
https://www.etoday.co.kr/news/view/2636777
https://www.segye.com/newsView/20261017503199
https://www.fnnews.com/news/202610151303320318
https://www.fnnews.com/news/202610161723353773
https://www.fnnews.com/news/202610140602364076
https://www.sisajournal.com/news/articleView.html?idxno=387462
https://www.newsis.com/view/NISX20260819_0003754748
Glossary
Circuit breaker — A mechanism that briefly halts trading when the index stays more than 8% below the previous day's close for one minute.
Net buying / net selling — If the amount bought over the same period is larger than the amount sold, it is net buying; if smaller, net selling.
Share buyback — When a company buys its own shares on the market. SK hynix plans to cancel (retire) all the shares it bought this time.
Other corporations — One line item in the exchange's statistics by investor type; a company's buyback of its own shares is included here.
BITPRESS articles are information to help your investment decisions, not a recommendation to buy or sell any stock or coin. Investment decisions and their results are your own responsibility.
