![Korea Market Close data snapshot for 2026-10-07: KOSPI 6,803.9 (-1.98%), KOSDAQ 898.43 (-2.34%), USD/KRW 1,339.3 (-0.05%), biggest moves we track Jusung Engineering (-11.13%) [en].](https://fermata.it.kr/wp-content/uploads/2026/10/kr_2026-10-07_editorial_en-39eaa3a496f7.png)
Jusung Engineering Soared 17% Yesterday. Why Did It Crash Today?
Today's Mood
KOSPI and KOSDAQ both slid for a second straight day. Bond yields and oil prices rose, and with Samsung Electronics’ preliminary Q3 results and a chip-ETF rebalancing both landing tomorrow (Oct 8), investors pulled back first.
Checking Yesterday's Call
The last session’s (Oct 6) article said to watch whether KOSPI retakes 7,000 on the day Samsung’s preliminary Q3 results and a chip-ETF rebalancing coincide — that’s tomorrow, Oct 8.
Today alone, the trend didn’t change: KOSPI closed at 6,803.90 (-1.98%), further from 7,000, and Samsung Electronics (-1.29%) and SK Hynix (-2.82%) both fell again. The real answer comes tomorrow.
KOSPI and KOSDAQ Fell Together Again
Rising bond yields and oil prices weighed on sentiment, and caution grew a day ahead of Samsung’s preliminary Q3 release tomorrow (Oct 8) (Money Today). A Kiwoom Securities analyst said the market would likely see limited upside and sector rotation as wait-and-see mode around Samsung’s preliminary results overlaps with caution ahead of the weekend (Money Today).
Foreigners sold 2.5961 trillion won and institutions sold 674.7 billion won of KOSPI, while individuals alone bought 2.5622 trillion won (Naver Finance, provisional as of 16:22). KOSDAQ fell even more, closing at 898.43 (-2.34%).
Jusung Engineering Gave Back Yesterday's Surge
KOSDAQ chip-equipment maker Jusung Engineering jumped 17.51% yesterday (Oct 6) to become KOSDAQ’s third-largest stock by market cap — up 739.35% year to date (Hankyung). Today it fell 11.13%, giving back part of that gain.
With rising market rates prompting profit-taking in large chip names, the money that had rotated into smaller equipment makers appears to have reversed just as quickly (Hankyung).
LG Electronics, LG Innotek: Earnings Backfired
LG Electronics posted Q3 operating profit of 781.8 billion won, up 13.5% from a year earlier, taking its first three quarters above 4 trillion won combined for the first time (Yonhap). Yet the stock fell 10.54% — operating profit missed the market estimate by 24.8% (Money Today).
LG Innotek fell 8.23%. DB Securities projects Q3 operating profit of 95.5 billion won, down 53.1% year on year, largely because the won strengthened from an average of 1,502 won per dollar in Q2 to 1,418 won in Q3 — a currency swing it estimates cut roughly 100 billion won from the prior quarter’s profit alone (Money Today). Still, DB Securities called the concern largely priced in and kept a Buy rating with a 950,000-won target.
Hyosung Heavy Industries (-7.8%), Daehan Optical (-3.18%), and SK Square (-1.64%) also fell.
Samsung, SK Hynix Answer Tomorrow
Valuations on both names still look cheap. By Naver Finance consensus, Samsung Electronics has 84.4% left to its target price and SK Hynix has 88.8% (on estimated P/Es of 5.8x and 4.9x). Both still fell today — Samsung 1.29%, SK Hynix 2.82% — because tomorrow (Oct 8) stacks earnings and flow events on the same day.
Samsung’s 15-trillion-won buyback program ended yesterday (Oct 6) (Hankyung) — one source of buying support disappeared as of today. Goldman Sachs cut its Q3 operating-profit estimate to 106 trillion won from 112 trillion won, and the market consensus has fallen to 105.5 trillion won from an August peak of 114 trillion won (Hankyung). Foreigners have sold $2.6 billion of Samsung over the last five sessions (Hankyung).
For beginners: P/E (price-to-earnings ratio) is price divided by earnings per share — lower means cheaper relative to profit. The percentage left to target price shows how much higher a brokerage’s target is than the current price. An ETF rebalancing is the periodic process of resetting a fund’s holding weights — when one stock exceeds its cap, the fund must mechanically sell the excess.
Only Cosmetics and Entertainment Rose
Few of the 79 sectors rose today. Broadcasting & entertainment (+3.84%), cosmetics (+3.78%), and road & rail transport (+3.55%) led, while electronics (-9.49%), electrical equipment (-5.33%), air freight & logistics (-4.79%), and aerospace & defense (-4.37%) fell the most.
Aerospace & defense fell even though Korea’s Nuri rocket launched successfully today (Yonhap) — the broader profit-taking across chips and electronics outweighed that good news.
Today's Biggest Movers
Jusung Engineering (-11.13%) was the day’s biggest decliner across both markets, followed by LG Electronics (-10.54%), LG Innotek (-8.23%), and Hyosung Heavy Industries (-7.8%). Among the stocks we follow, Hanwha Aerospace (-4.99%), HD Hyundai Heavy Industries (-4.88%), Hanmi Semiconductor (-4.86%), and Samsung Electro-Mechanics (-4.24%) fell sharply.
Gainers were rare: APR (+4.99%) stood out, while KB Financial (+0.96%), Celltrion (+0.6%), and LG Energy Solution (+0.26%) edged up.
Foreigners and Institutions Sold, Individuals Bought
Foreigners sold 2.5961 trillion won and institutions sold 674.7 billion won of KOSPI today; individuals absorbed it with 2.5622 trillion won in net buying (Naver Finance, provisional as of 16:22). KOSDAQ saw the same pattern — foreigners sold 258.6 billion won, institutions sold 217 billion won, and individuals alone bought 501.9 billion won.
Yesterday's LG Buyers Saw the Opposite Today
Today’s stock-level flow data isn’t out yet, so we’re looking at the last session (Oct 6). That day, foreigners bought 198,112 shares of LG Electronics and institutions bought 203,719 shares — both buying. LG Innotek was the same: foreigners bought 71,367 shares, institutions 78,636.
Shinhan Financial Group split the other way — foreigners sold 181,475 shares while institutions bought 120,180. That foreigners and institutions both bought LG Electronics and LG Innotek yesterday, only for both stocks to slide on earnings concerns today, shows how fast flows and fundamentals can diverge.
Wall Street Set Fresh Records Overnight
In the last session (Oct 5), the Nasdaq Composite rose 1.05%, outpacing the Dow (0.18%) and S&P 500 (0.66%). The 10-year Treasury yield climbed to 5.31%, a 90-day high, while the VIX stayed low at 15.52.
While Wall Street keeps setting records, KOSPI keeps failing to hold 7,000 — a clear gap in mood between the two markets.
The Won Edged Lower
The won closed at 1,339.3 per dollar on Hana Bank’s reference rate, down 0.05% from the previous day. That the currency barely moved even as US yields rose suggests foreign selling in local equities hasn’t yet spilled into serious pressure on the won.
Tomorrow (Oct 8), Samsung Answers With Numbers
Tomorrow is Samsung Electronics’ preliminary Q3 earnings release. Goldman Sachs sees 106 trillion won in operating profit and the market consensus sees 105.5 trillion won — both down from August peaks (Goldman: 112 trillion won; market: 114 trillion won) (Hankyung).
The same day brings the periodic rebalancing of seven chip ETFs (combined 18.94 trillion won) and options expiration — so-called quadruple witching day (Seoul Economic Daily, Hankyung). Samsung’s weight in the TIGER Semiconductor TOP10 ETF, at 26.98%, exceeds its 25% cap, implying roughly 210 billion won in mechanical selling, while SK Hynix (about 90 billion won) and SK Square could see offsetting buying (Seoul Economic Daily). With earnings and flows colliding on the same day, we expect tomorrow to decide whether KOSPI slips further below 6,800 or tries again for 7,000.
Three Things Collide on Samsung Tomorrow
Seven Chip ETFs Trim Samsung's Weight First
Seven Korean chip ETFs with combined net assets of 18.94 trillion won (as of Oct 2) undergo periodic rebalancing on Oct 8 (Seoul Economic Daily). One of them, TIGER Semiconductor TOP10, caps any single holding at 25%; Samsung Electronics currently sits at 26.98%, 1.98 percentage points over that cap, implying roughly 210 billion won in mechanical selling (Seoul Economic Daily).
SK Hynix and SK Square, by contrast, are expected to see roughly 90 billion won each in buying demand (Seoul Economic Daily) — money leaving Samsung could rotate into SK Hynix, SK Square, and smaller chip-equipment names.
The same day, Samsung’s 15-trillion-won buyback program wrapped up the day before (Oct 6), and options expiration (quadruple witching) lands too (Money Today, Seoul Economic Daily). Earnings, rebalancing, options expiration, and the end of a buyback rarely converge on a single day, and brokerages are bracing for added volatility (Hankyung).
| Rebalancing ETF assets | 18.94tn won (7 funds) |
| Samsung's current weight (TIGER Semi TOP10) | 26.98% (cap 25%) |
| Samsung's expected selling | ~210bn won |
| SK Hynix's expected buying demand | ~90bn won |
Fermata’s Take
We’re not buying Samsung Electronics or SK Hynix today either. By Naver Finance consensus, Samsung Electronics has 84.4% left to its target price and SK Hynix has 88.8%, so valuation looks cheap. But Samsung’s 15-trillion-won buyback ended yesterday, Goldman Sachs and the market consensus have both cut profit estimates, and foreigners have sold Samsung for five straight sessions.
Tomorrow stacks earnings, an ETF rebalancing, and options expiration on the same day, so volatility could pick up. We’ll treat it as a buying opportunity if results beat consensus (105.5 trillion won operating profit) and the stock still falls on rebalancing-driven selling. If results miss, we’ll brace for further downside instead.
Check · 2026-10-08 — On the day Samsung's preliminary Q3 results (market consensus: 105.5 trillion won operating profit; Goldman Sachs: 106 trillion won) coincide with the periodic rebalancing of seven chip ETFs (combined 18.94 trillion won) and options expiration, we'll check whether KOSPI falls further below 6,800 or tries again for 7,000, and how Samsung Electronics and SK Hynix react.