TODAY IN ONE LINEOil pressured the morning; buying support held the 7,000 line
KOSPI7,033.92 -0.25%
KOSDAQ836.92 +0.79%
SNOWSHAGAL · DAILY
MARKET RESEARCH
2026.09.10 · THU KRX CLOSE 15:30
DAILY MARKET NOTE / 10 SEP 2026
Down to 6,898, Back Above 7,000 on Expiry Day
KOSPI -0.25% · recovered most of a drop of more than 2% intraday · KOSDAQ closed +0.79% higherThe main drivers of the morning decline were higher oil prices and U.S. long-term yields after the U.S.-Iran military clash · Brent crude back above $100 coincided with the KRX semiconductor index periodic rebalancing · foreign selling concentrated in large-cap semiconductors, while institutions and other corporations bought heavily on the other side
The index returned near the previous close, but advancers again fell below half the market · what held the 7,000 line was not broad buying, but concentrated buying that absorbed supply
KOSPI
7,033.92
-0.25%
KOSDAQ
836.92
+0.79%
MARKET PATH / 01
The first 90 minutes sold off; 7,000 returned after lunch
When did direction change, and what was working then?
KOSPI · 09:00~15:307,038.85 open → 7,072.79 → 6,898.45 → 7,033.92 close · recovered 135.47 points from the low
7,0006,900Previous close 7,051.647,072.79Early 09:00s · intraday high6,898.4510:30 lowTurned positive around 14:307,033.92Closing call auction09:0012:0015:30
OPEN7,038.85-0.18%
HIGH7,072.79+0.30%
LOW6,898.45-2.17%
CLOSE7,033.92-0.25%
THE READ
The morning plunge was where the Korean market absorbed, in the first 90 minutes after the open, the oil-and-rate burden already priced overnight · the low was set once, at 10:30The afternoon recovery did not come from bad news fading; it came because buying that absorbed sell orders became stronger · oil remained near the previous day's close even around the Korean market closeThe move back above the previous close around 14:30 was reversed to -0.25% by the · an expiry-day close is a weak directional signalKOSDAQ also recovered from a low down more than 2% to finish positive · its reversal from the morning shock was larger than KOSPI's
OPEN · MORNING
From the opening high to the 10:30 low, one direction
Opened at 7,038.85, below the previous close · briefly turned positive at 7,072.79 in the early 09:00s, then immediately reversed lowerBroke below 7,000 at 09:43 at 6,964.39 · set the day's low at 6,898.45 at 10:30KOSDAQ was also pushed down to the 813 area at the same time, with both markets moving in the same direction
MIDDAY · AFTERNOON
Stepwise recovery from 11:10
After the 10:30 low, traded between the low 6,900s and 6,950 through 11:10 · then recovered one step at a timeAt 12:45, the moved back above 7,000; the 13:00 hour was a battle around that level · 7,029.48 at 13:39KOSDAQ moved back toward flat around 13:20, then turned positive
CLOSE
Positive around 14:30, then pushed back in the closing auction
The 14:30 5-minute bar rose about 20 points and moved above the previous close · the same interval as TSMC's record August revenue announcement at 14:30 Korea timeTSMC was not the cause of an afternoon recovery already under way, but an additional catalyst that supported the late narrowing of semiconductor lossesStayed near 7,050 until just before the 15:20 call-auction period · slipped to 7,033.92 in the closing auction · the final bar had the day's highest volume KOSPI 46.0% · KOSDAQ 47.6%, both below half
Intraday path from KOSPI 5-minute closes · open, high, low and close are final KRX values · the first 10 minutes are marked with the 09:02 reported index level and the day's high · 15:20 to 15:30 is the closing call-auction period · horizontal dotted line: previous close 7,051.64.
WHY / 02
Oil and yields pressured the morning; expiry amplified volatility
Only the factors that actually explained the day's direction
01
The main driver of the morning plunge was higher oil and U.S. long-term yields after the U.S.-Iran clash
On local September 9, U.S. Central Command said it had destroyed five Iranian tankers in response to attacks by Iran's · Iran claimed it had launched a missile attack on a U.S. military base in JordanBrent crude closed above $100 for the first time since July 23 · the U.S. 10-year yield topped 4.85% intraday, the highest since November 2023Oil fed inflation concerns, and those concerns fed into yields overnight · all three major U.S. equity indexes fell, while the weakest Korean sectors near the morning low were construction, machinery & equipment, electricity & gas, and chemicals
$101.21Brent crude September 9 close · up 3.36% on the day
View evidence
WTI $96.05 +3.25% · both benchmarks closed near their highest levels since May
Iran's IRGC warned it would expand its maritime-control zone from the Strait of Hormuz into parts of the Gulf of Oman and Arabian Sea · it also mentioned cutting shipping and insurance services to vessels that violate the rules
U.S. equities September 9 · Dow -0.77% · S&P500 -0.48% · Nasdaq -0.64% · Philadelphia Semiconductor Index +0.37%, with semiconductors the only pocket holding up
U.S. 10-year yield closed at 4.837%, up from 4.806% the prior day · reports also said disappointment over the size of U.S. Treasury debt purchases contributed to upward pressure on yields
Around 16:00 Korea time, after the Korean close, WTI was $95.72 · near the previous day's $96.05 close
02
What amplified trading and volatility was the overlap of quadruple witching and the KRX semiconductor index on the same day
Periodic changes to 29 KRX sector indexes · 33 tracking ETFs with about KRW 11.7tn in net assets · a 20% single-stock cap applied to the semiconductor indexStreet estimates put sell flow at about KRW 1.244tn for SK hynix and KRW 206.8bn for Samsung Electronics · executions were expected to concentrate near the close (Mirae Asset Securities estimate)The imprint was clearer in trading volume than in direction · KOSPI turnover was nearly one-third above the 5-day average
131.8%KOSPI turnover KRW 28.193tn · versus the 5-day average
View evidence
The rebalancing takes effect September 11 · related trades are structured to execute at the September 10 close, the session before the effective date
Top estimated buys on the weight-increase side were Hanmi Semiconductor, Jusung Engineering, LEENO Industrial and EO Technics · company-level amounts and actual investor flows are in CHANGE
Previous-session turnover KRW 22.276tn · KOSDAQ turnover KRW 11.314tn, 168.4% of the 5-day average
MONEY / 03
Foreign selling concentrated in two semiconductor names · institutions and large other-corporation buying stood opposite
Who moved today's index
FOREIGN · KOSPI CASH
-KRW 2.482tn
No. 1 net sell: SK hynix · No. 2: Samsung Electronics · the two accounted for 55.5% of the KRW 5.7233tn in net-sold stocksAt 14:20, -KRW 1.0288tn → final close -KRW 2.482tn · a clear sign that foreign selling pressure expanded sharply into the closeSelling extended beyond the two large caps to semiconductor equipment and foundry names including Hanmi Semiconductor, Wonik IPS and DB HiTek
SK hynix-KRW 1.7695tn
Samsung Electronics-KRW 1.4062tn
Hanmi Semiconductor-KRW 255.8bn
Wonik IPS-KRW 142.9bn
INSTITUTION
+KRW 433.4bnSamsung Electronics +KRW 1.0119tn · SK hynix +KRW 533.2bn, standing opposite foreign selling · at 13:20 preliminary -KRW 1.5217tn then flipped to positive by the close · on KOSDAQ as well, +KRW 1.3488tn supported the positive close
INDIVIDUAL
+KRW 380.1bnAt 13:20 preliminary +KRW 1.5713tn, then narrowed · No. 1 net sell was Samsung Electronics preferred shares -KRW 178.9bn
OTHER CORP ·
+KRW 1.667tn
Final KRX figure · market-wide basis · market reports focused on treasury-share purchases by Samsung Electronics and SK hynix · the back-solved total outside the three main investor groups for those two stocks was KRW 1.6229tn, similar in scale, but it is not a direct company-level 'other corporations' figure and is therefore not attributed to the two stocks
Futures · program trading · intraday flows · stock-level flows
Foreign KOSPI 200 futures-KRW 1.947tn
Institutional KOSPI 200 futures+KRW 1.841tn
KOSPI program trading-KRW 2.5245tn
Program trading-KRW 2.9648tn
Program trading split between arbitrage +KRW 440.3bn and non-arbitrage -KRW 2.9648tn · selling expanded from the previous session's total of -KRW 322.1bn, with selling expanding in scale
Intraday preliminary figures (reported) · at 10:30 foreign investors -KRW 444.2bn · institutions -KRW 639.8bn · individuals +KRW 648.1bn · other corporations +KRW 433.1bn
At 13:20 foreign investors -KRW 1.2038tn · institutions -KRW 1.5217tn · individuals +KRW 1.5713tn / at 14:20 foreign investors -KRW 1.0288tn · institutions -KRW 924.6bn · individuals +KRW 465.5bn · other corporations +KRW 1.4860tn
Preliminary intraday figures and final close figures are compiled at different times, so interval comparisons are used only to check direction · headline totals use final KRX figures
Residual outside the three main investor groups +KRW 1.6685tn = other corporations +KRW 1.6670tn + other investor categories KRW 1.5bn
Samsung Electronics: foreign investors -KRW 1.4062tn · institutions +KRW 1.0119tn · individuals -KRW 118.3bn · back-solved outside the three main groups +KRW 512.6bn / SK hynix: foreign investors -KRW 1.7695tn · institutions +KRW 533.2bn · individuals +KRW 126.0bn · back-solved outside the three main groups +KRW 1.1103tn
Samsung Electronics controlling-shareholder transaction · Executive Chairman Lee Jae-yong plans an off-market purchase of 7,188,793 shares held by Honorary Director Hong Ra-hee (disclosed after the September 9 close) · scheduled transaction date: October 12 · about KRW 1.9374tn based on the September 8 close of KRW 269,500 · actual quantity and price may vary within 70-130% of the plan · because this is an off-market transaction that has not yet executed, it is unrelated to today's investor flow data
Next in foreign net selling: DB HiTek -KRW 136.8bn · EO Technics -KRW 121.2bn / No. 1 net buy: Samsung Electronics preferred shares +KRW 143.0bn · SK Square +KRW 126.4bn · Hyundai Mobis +KRW 70.2bn
Next in institutional net buying: Hanmi Semiconductor +KRW 318.1bn · Jusung Engineering +KRW 236.8bn · Wonik IPS +KRW 138.7bn · TSE +KRW 132.2bn / No. 1 net sell: SK Square -KRW 143.7bn · Hyundai Mobis -KRW 85.7bn · Samsung Electro-Mechanics -KRW 72.5bn
Individual net buys: SK hynix +KRW 126.0bn · Samsung Electro-Mechanics +KRW 85.5bn · Doosan Enerbility +KRW 59.5bn / net sells: Samsung Electronics preferred shares -KRW 178.9bn · Samsung Electronics -KRW 118.3bn · Jusung Engineering -KRW 117.3bn
Buy/sell The denominator for concentration is the sum of the values of all stocks that the investor group net bought (or net sold), not the market-wide net figure · aggregated from raw KRX data · stock-market-wide figure combining KOSPI and KOSDAQ · total foreign net-sold stocks KRW 5.7233tn · total institutional net-bought stocks KRW 4.2343tn, of which Samsung Electronics accounted for 23.9%
The gap between spot KOSPI 200 at 1,112.13 (15:30 close) and futures at 1,115.80 (15:45 close) was 3.67 · because the closing times differ, it is not used as directional evidence
KOSDAQ institutions +KRW 1.3488tn · foreign investors -KRW 1.0756tn · individuals -KRW 269.8bn
KOSPI share rose from 4.69% to 5.32% · value KRW 1.874tn · KOSDAQ KRW 807.5bn, 6.37% · based on regular-market trading across KRX and NXT, so the denominator differs from KOSPI turnover
SECTOR / 04
Where the market was strong · where it was weak
Today's distribution of strength and weakness, not a ranking table
STRONG
KOSPI Medical & Precision Instruments+2.25%
KOSDAQ Transportation Equipment & Parts+2.08%
KOSDAQ Electrical & Electronics+1.82%
KOSPI Insurance+1.64%
WEAK
KOSPI Electricity & Gas-2.02%
KOSPI Pharmaceuticals-1.52%
KOSPI Chemicals-1.42%
KOSPI Telecommunications-1.35%
The weakest end was KOSPI Electricity & Gas and Chemicals · construction also sold off near the morning low but recovered to finish positive, while these two sectors were left behind in the reboundElectricity & Gas, however, had 7 advancers out of 10 stocks, so the sector-index decline was not broad-based weakness; it was driven by large-cap names at the top of the market-cap rangeAt the strong end were Insurance, which can be read as benefiting from higher yields (11 advancers out of 13), and two KOSDAQ groups: equipment and partsKOSPI Medical & Precision Instruments +2.25% had only 2 advancers out of 8 stocks · do not read the index gain as sector-wide strengthA single day's move is not enough to call a leadership shift
Sector evidence
Of 46 KRX industry indexes, 30 rose and 16 fell · on KOSPI, 13 of 24 rose · on KOSDAQ, 17 of 22 rose
Weakest sectors at 10:30 (reported) · Construction -2.97% · Machinery & Equipment -2.73% · Electricity & Gas -2.70% · Chemicals -2.38% → close: Construction +0.26% · Machinery & Equipment -1.03% · Electricity & Gas -2.02% · Chemicals -1.42%
Weak-side detail · in KOSPI Electricity & Gas, 7 of 10 stocks rose even as the sector index fell · a structure in which the largest market-cap names pulled down the index · in KOSPI Chemicals, 64 of 122 traded stocks declined
Strong-side detail · 163 of 316 KOSDAQ Electrical & Electronics stocks rose · 44 of 77 KOSDAQ Transportation Equipment & Parts stocks rose · because the indexes are market-cap weighted, a few large stocks lifted the sector returns
Of 39 theme indexes, 15 rose, 1 was flat and 23 fell · strongest: KOSDAQ 150 Governance +1.88% · K-AI Defense TOP5+ +1.41% · KRX AI Semiconductor +0.99%
Weak themes · KRX Shipbuilding TOP10 -1.74% · KRX-Akros AI Power Infrastructure -1.40% · Bio TOP 10 -1.18% · Secondary Battery TOP 10 -1.04%
Single-stock event · S-Oil disclosed a KRW 4.1152tn petroleum-products supply contract with NongHyup Economic Holdings (12% of recent revenue · through September 2027), but the share price fell intraday more than 7% · meanwhile, oil distributors such as Heungkuk Oil and JoongAng Enervis posted double-digit gains in the morning · a case where the disclosure and price moved in opposite directions
Four of the top 10 stocks by market capitalization rose · Samsung Electronics preferred shares +2.78% · Samsung Life Insurance +1.98% · Samsung C&T +0.93% · Hyundai Motor +0.26% / decliners: Samsung Biologics -2.00% · LG Energy Solution -1.62% · Samsung Electro-Mechanics -0.28% · SK Square -0.26% · Samsung Electronics -0.19% · SK hynix -0.16%
Sectors andare not mixed into one ranking table · sector returns are market-cap-weighted index moves, not sector-level net inflow amounts
CHANGE / 05
Answers to yesterday's questions
Checking the conditions set in the previous edition
YESTERDAY → TODAY
The first question, the advancing-share ratio, fell back below half from 50.7% to 46.0% · KOSDAQ also fell from 55.7% to 47.6% · breadth did not carry through even on a day when the index recovered sharply from its lowFor the second question, the two stocks exposed to quadruple witching and the rebalancing were SK hynix -0.16% and Samsung Electronics -0.19%, with only limited closing-price impactFor the four names expected to gain index weight, institutional net buying was broadly similar in size to Street estimates, but foreign investors sold roughly comparable amounts in the same names, splitting the stock-price outcomes (interpretation) · Jusung Engineering +7.02% · Hanmi Semiconductor +1.00% / LEENO Industrial -1.14% · EO Technics -3.19%The power-infrastructure and secondary-battery themes that were strong in yesterday's third question both reversed lower after one day
01
KOSPI advancing-share ratio
50.7%
→
46.0%
02
KRX-Akros AI Power Infrastructure
+6.38%
→
-1.40%
03
KRX K-AI Secondary Battery
+8.22%
→
-0.65%
Flows in stocks with increased rebalancing weights
Hanmi Semiconductor · institutions +KRW 318.1bn · foreign investors -KRW 255.8bn · individuals -KRW 61.6bn · estimated buy flow about KRW 306.4bn
Jusung Engineering · institutions +KRW 236.8bn · foreign investors -KRW 116.5bn · individuals -KRW 117.3bn · estimated buy flow KRW 179.5bn
LEENO Industrial · institutions +KRW 109.0bn · foreign investors -KRW 103.0bn · individuals -KRW 5.6bn · estimated buy flow KRW 144.3bn
EO Technics · institutions +KRW 130.3bn · foreign investors -KRW 121.2bn · individuals -KRW 8.6bn · estimated buy flow KRW 124.1bn
Estimated buy flows are from Mirae Asset Securities · stock-level flows are raw KRX investor-trading data · institutional net buying includes trades unrelated to the rebalancing, so the two figures are not matched one-for-one
NEXT / 06
What to check in the next session
Conditions that can be scored from actual outcomes, not probabilities
Does foreign cash-equity net selling stay above KRW 1tn the day after expiry?
Today's KRW 2.482tn came on a session where expiry and the index rebalancing overlapped · if selling above KRW 1tn continues into the next session, the balance of evidence shifts from schedule-driven flow toward directional selling · check the sign of foreign KOSPI 200 futures alongside it
After U.S. August PPI, does the U.S. 10-year yield close above 4.85%?
This tests whether the morning selloff's transmission path really ran from oil to rates · if the 10-year closes above 4.85%, also check whether Korean Chemicals and Electricity & Gas remain among the weakest sectors in the next session
Does KOSPI close above 7,000 for a third straight session while the advancing-share ratio recovers above 50%?
The closing level held, but only 46.0% of stocks advanced · if the index holds while breadth stays below half, read the resilience as dependent on concentrated buying that absorbs supply
TONIGHT → NEXT SESSION · 9/11
Rate decision · released
All three policy rates raised by 0.25 percentage point · deposit facility rate 2.50% · response to energy-price-driven inflation pressure
U.S. August · released
+0.4% month over month · +5.4% year over year, above the 5.3% consensus · the final inflation check before the next day's CPI
Korean market open
First session after expiry and rebalancing flows · index changes take effect
9/11-9/17 macro calendar
U.S. August CPI
Due 08:30 local time · the final inflation reading before the September Fed decision
Federal Reserve rate decision
September 16, 14:00 local time · September 17, 03:00 Korea time
Buying that absorbed supply filled the morning gap, but the final call auction pulled the market back down again on expiry day.
Sources · data conventions
As of 2026.09.10 · Korean market final close at 15:30
Indexes · breadth · turnover · Naver Finance daily index data and final KRX close data
Investor totals · final KRX figures (KOSPI foreign investors · individuals · institutions · other corporations; KOSDAQ three main investor groups cited from closing-market reports)
Intraday path · KOSPI 5-minute closes · open, high, low and close are final KRX values · 09:02, 09:43, 10:30 and 13:39 index levels are from market reports
Intraday preliminary flows · preliminary Securities Market figures reported at 10:30, 13:20 and 14:20 · compiled on a different basis from final totals, so used only to check direction
Stock-level flows · final KRX investor-trading raw data · whole stock-market basis · concentration denominators are sums from the raw data
Sectors · themes · KRX Index industry and theme indexes at the close · 10:30 sector moves are based on market reports
Program trading · futures · short selling · final KRX figures · short-selling data combine regular-market KRX and NXT
Overseas · U.S. equity indexes and Philadelphia Semiconductor Index at September 9 close · U.S. 10-year close 4.837% · Brent and WTI at September 9 close · WTI $95.72 is the level around 16:00 Korea time on September 10
Reports · U.S. Central Command announcement that five Iranian tankers were destroyed and Iran's claim of an attack on a U.S. base in Jordan (local September 9), IRGC warning on expanding the maritime-control zone, U.S. 10-year yield exceeding 4.85% intraday, and assessments of U.S. Treasury debt-purchase size
TSMC · August revenue TWD 514.8bn, a record monthly high · up 10.1% month over month · released at 13:30 Taiwan time (14:30 Korea time)
Periodic rebalancing · 29 KRX sector-index changes, size of 33 tracking ETFs, 20% cap in the semiconductor index, and estimated stock-level sell/buy flows based on Mirae Asset Securities reports
Other corporations · final KRX figure · treasury-share-purchase explanation based on closing-market reports · stock-level values outside the three main investor groups are back-solved from raw data
Additional stock-level returns · top 10 by market capitalization use final KRX closes · Jusung Engineering and Hanmi Semiconductor use final closes in KRX short-selling data · LEENO Industrial and EO Technics use closing-market reports
Calendar · ECB rate decision September 10, 14:15 local time · U.S. PPI September 10, 08:30 local time · CPI September 11, 08:30 local time · Federal Reserve rate decision September 16, 14:00 local time
Released after the Korean close · ECB decision and U.S. PPI results
Corporate disclosures · S-Oil single-sale/supply contract (September 10) · Samsung Electronics controlling-shareholder off-market transaction plan (after the September 9 close)
Additional single-stock returns · S-Oil based on intraday price at 10:29 · oil distributors based on 10:00 feature-stock reports
