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Weekly wrap · Week of Sep 14 – Sep 18, 2026 · 5 trading days

KOSPI slips 0.2% for the week as foreign selling offsets Friday's chip rebound; KOSDAQ gains 0.8%

KOSPI−0.2%KOSDAQ+0.8%KOSPI 2000.0%

The week was shaped by a US rate move and a late chip rebound. The Fed raised its benchmark rate by 0.25 point to 3.75-4.00%, its first hike since July 2023, and left room for more tightening. The won weakened to about ₩1,382 per dollar. Reports said foreigners sold ₩2.28 trillion on Sept 17, while treasury-share buying tied to Samsung Electronics and SK hynix cushioned the index. Securities firms fell 2.8%, with Mirae Asset Securities down 5.4%.

On Sept 15, reports cited the US 10-year yield back above 5%, oil near $100 and worries about the pace of AI demand; KOSPI fell 0.85% that day while KOSDAQ rose. On Sept 18, foreigners turned net buyers after eight straight sell sessions and KOSPI rose 2.7% to 6,894.2. The sources cite easing oil and yields, a rally in US chip stocks and the Nvidia CEO's comment that next year's chip sales could roughly double. SK hynix closed the week up 2.5% and Samsung Electronics up 0.6%. In company news, Orum Therapeutics fell 26.7% after a clinical halt of a licensed drug candidate; reports say an $80 million milestone is unlikely, with no return of the $100 million upfront fee.

Why the market moved

KOSPI slipped on a Fed hike, oil near $100 and a 10-year yield above 5%, then rebounded Friday as oil and yields eased and the Nvidia CEO's comments lifted chips.1234

Top themes

Power grid & cables

Foreign buying of cable makers; no clear reason reported1

Optical & telecom

Foreign net buying of Taihan Fiberoptics1

Semiconductors

Nvidia CEO sales comment; US chip rally12

The big stories

Fed hikes rates for first time since 2023; KOSPI holds near 6,715

The Fed raised its benchmark rate by 0.25 point to 3.75-4.00%, its first hike since July 2023, and left room for further tightening. KOSPI closed down 0.22% on the day as foreign investors sold KRW 2.28 trillion, though institutional buying of Samsung Electronics and SK hynix treasury shares cushioned the index.1234

Directly affected

  • weak-won—Won weakened to about 1,382 per dollar as the US rate hike widened the rate gap

Next in line

Rate, oil and AI-pace worries push KOSPI lower on Sept 15

Reports say the US 10-year yield rose back above 5% and oil neared $100 a barrel, with concerns about slowing AI-driven demand adding pressure. Foreign and institutional investors sold heavily that day, and KOSPI closed lower while KOSDAQ rose.123

Directly affected

Next in line

  • Data centers+1.2%Doubts about the pace of AI investment affect data center demand outlookKinx +1.2%

Further out

Foreign buying returns after eight sessions; SK hynix leads chip rebound

Foreign investors turned net buyers on Sept 18 after eight straight sell days, and KOSPI rose to about 6,890 on chip strength. SK hynix closed up 2.48% and Samsung Electronics up 0.58%, after Nvidia's CEO said next year's chip sales could roughly double and US chip stocks rallied.1234567

Directly affected

Next in line

Sungho Electronics surges 53% after convertible bond call option exercise

Sungho Electronics filed notice of exercising its convertible bond call option and its shares rose 53.3% on the day. The stock had already climbed through the week, reaching KRW 22,200 on Sept 17.12

Directly affected

Further out

  • On-device AI+1.4%Shares moved with a wider rally in Apple foldable-iPhone related stocksNota +1.4%

Orum Therapeutics plunges 27% after clinical trial halt

Orum Therapeutics shares fell 26.7% after a technology-export drug candidate was halted in clinical development. Reports say the company is unlikely to receive an $80 million milestone payment, though it does not have to return the $100 million upfront fee.1234

Directly affected

Next in line

The market

KOSPI fell 0.2% to 6,894.2, KOSDAQ rose 0.8% to 827.1, and KOSPI 200 was little changed at 1,090.2 (+0.0%). Advancers numbered 1,326 against 1,164 decliners, with 273 unchanged. Weekly trading value was about ₩35.7 trillion versus an average of about ₩28.4 trillion. Foreigners were net sellers of about ₩8.8 trillion on KOSPI and about ₩89.8 billion on KOSDAQ. USD/KRW was 1,380.3, up 3.1% over the week; the 3-year KTB yield was 4.035% and the US 10-year 5.01%.

KOSPIDaily closes · shaded: this wrap6,894.23
6,0007,0008,0009,000
Jun 8Jul 10Aug 14Sep 18
KOSDAQDaily closes · shaded: this wrap827.12
7008009001,000
Jun 8Jul 10Aug 14Sep 18

1,326 stocks rose, 1,164 fell · trading value ₩36T

USD/KRW1,380.3+3.1%
KTB 3y4.04+2bp
UST 10y5.01—

Themes investors follow

Space & aerospace rose 8.8%, led by Nara Space Technology (+40.4%) and Kencoa Aerospace (+32.1%). Power grid & cables gained 8.5%: Gaon Cable rose 28.7% and Seondo Electric 22.1%, while Korea Electric Power fell 7.1%. Telecom & 5G rose 7.4%, led by Taihan Fiberoptics (+29.5%). K-defense rose 5.4% with Vitzro Tech up 30.9%. HBM & AI chips rose 4.1% and semiconductor equipment 4.0%, with Sensorview up 60.5%. On the downside, casinos fell 3.8%, ADC & cancer drugs 3.7% (ABL Bio -15.3%), insurance 3.5%, carmakers 3.3%, fintech 3.3% (kakaopay -13.0%) and shipbuilding 1.7%. Robots were roughly flat (-0.1%) and AI software fell 1.1%.

Popular themes

Best themes

  • Space & aerospace+8.8%Nara Space Technology +40.4% · Kencoa Aerospace +32.1% · Lumir +13.0%
  • Power grid & cables+8.5%Gaon Cable +28.7% · Seondo Electric +22.1% · IL +8.6%
  • Telecom & 5G+7.4%Taihan Fiberoptics +29.5% · Gigalane +26.3% · KMW +25.8%
  • K-defense+5.4%Vitzro Tech +30.9% · KP Aero Industries +17.1% · Vitzro Nextech +15.2%
  • Smartphone parts+4.4%Amosense +37.0% · DK Tech +34.3% · Dreamtech +19.6%
  • HBM & AI chips+4.1%HVM +24.5% · SK hynix +2.5% · Hanmi Semiconductor +2.2%

Worst themes

  • Casinos−3.8%Kortek −6.3% · Kangwon Land −3.5% · Paradise −3.3%
  • ADC & cancer drugs−3.7%ABL Bio −15.3% · LigaChem Biosciences −3.5% · HLB Therapeutics −3.5%
  • Aesthetics & botox−3.6%Hugel −7.4% · Humedix −4.8% · PharmaResearch −4.2%
  • Insurance−3.5%Samsung Life Insurance −7.8% · Samsung Fire & Marine Insurance −5.5% · Seoul Guarantee Insurance −5.3%
  • Hyundai & Kia (carmakers)−3.3%KG Mobility −4.8% · Hyundai Motor −4.6% · KIA −3.7%
  • Fintech & payments−3.3%kakaopay −13.0% · Hecto Financial −12.8% · Danal −10.7%

The biggest companies

SK hynix rose 2.5% and Samsung Electronics 0.6% on chip demand. SK Square fell 0.9%, Samsung Electro-Mechanics 0.9%, and LG Energy Solution rose 1.1%. Hyundai Motor fell 4.6%, Samsung Biologics 1.2%, KB Financial 1.7% and Samsung C&T 4.4%. Samsung Life Insurance fell 7.8%, Doosan Enerbility 6.5%, Shinhan Financial 2.5%, HD Hyundai Heavy Industries 4.0% and KIA 3.7%. Hanwha Aerospace slipped 0.3%. No clear reason was reported for most of these declines; the sources point to rates and foreign selling for financials.

Who was buying and selling

Foreigners sold SK hynix (about ₩3.4 trillion), Samsung Electronics (about ₩2.6 trillion) and Samsung Electronics Pref. (about ₩551 billion), and bought Taihan Fiberoptics (about ₩149.6 billion, +29.5%), Gaon Cable (about ₩117.5 billion, +28.7%) and Hyundai Movex. Institutions bought Samsung Electronics Pref., Samsung Electronics and Hanmi Pharm (+8.4%), and sold SK Square and Doosan Enerbility. Retail bought Netmarble, Samsung Electronics Pref. and Doosan Enerbility (-6.5%), and sold SK hynix (about ₩2.0 trillion) and the two cable names.

Foreign investors

Net bought

  1. 1Taihan Fiberoptics+₩150B+29.5%
  2. 2Gaon Cable+₩117B+28.7%
  3. 3Hyundai Movex+₩78B+3.9%
  4. 4SK Square+₩72B−0.9%
  5. 5GS Holdings+₩57B−4.3%
  6. 6LG Innotek+₩50B−2.0%
  7. 7Wonik IPS+₩39B+10.2%
  8. 8LIG Defense&Aerospace+₩39B+9.7%
  9. 9SFA Semicon+₩35B+28.1%
  10. 10Sanil Electric+₩35B+6.5%
  11. 11Alteogen+₩33B−5.4%
  12. 12Woori Financial Group+₩28B+2.8%
  13. 13Daeduck Electronics+₩27B+3.2%
  14. 14LS Electric+₩27B+3.4%
  15. 15Hanmi Semiconductor+₩27B+2.2%

Net sold

  1. 1SK hynix−₩3.4T+2.5%
  2. 2Samsung Electronics−₩2.6T+0.6%
  3. 3Samsung Electronics Pref.−₩551B+1.5%
  4. 4Netmarble−₩374B−1.6%
  5. 5Doosan−₩232B+6.7%
  6. 6Doosan Enerbility−₩200B−6.5%
  7. 7KB Financial Group−₩115B−1.7%
  8. 8DB HiTek−₩101B+19.2%
  9. 9Jusung Engineering−₩74B−1.7%
  10. 10Hanmi Pharm−₩69B+8.4%
  11. 11NAVER−₩68B−4.3%
  12. 12Korea Electric Power−₩53B−7.1%
  13. 13Shinhan Financial Group−₩52B−2.5%
  14. 14HD Hyundai Electric−₩50B−2.9%
  15. 15Isupetasys−₩50B−5.6%

Institutions

Net bought

  1. 1Samsung Electronics Pref.+₩163B+1.5%
  2. 2Samsung Electronics+₩152B+0.6%
  3. 3Hanmi Pharm+₩125B+8.4%
  4. 4KB Financial Group+₩113B−1.7%
  5. 5Samsung Electro-Mechanics+₩97B−0.9%
  6. 6Doosan+₩93B+6.7%
  7. 7LG Energy Solution+₩76B+1.1%
  8. 8Samsung E&A+₩64B+1.6%
  9. 9Shinhan Financial Group+₩54B−2.5%
  10. 10Samyang Foods+₩49B+1.7%
  11. 11LG Chem+₩46B−2.2%
  12. 12Hanwha Engine+₩43B+2.0%
  13. 13Hanwha Systems+₩43B+12.8%
  14. 14Amorepacific+₩42B+2.1%
  15. 15DB HiTek+₩41B+19.2%

Net sold

  1. 1SK Square−₩172B−0.9%
  2. 2Doosan Enerbility−₩107B−6.5%
  3. 3NAVER−₩98B−4.3%
  4. 4Isupetasys−₩58B−5.6%
  5. 5SK hynix−₩48B+2.5%
  6. 6Hyundai Motor−₩47B−4.6%
  7. 7Hyundai Mobis−₩47B−8.8%
  8. 8L&F−₩39B−7.5%
  9. 9KEPCO Engineering & Construction−₩38B−12.0%
  10. 10GS Holdings−₩37B−4.3%
  11. 11Alteogen−₩36B−5.4%
  12. 12LG Innotek−₩36B−2.0%
  13. 13Hanmi Semiconductor−₩35B+2.2%
  14. 14APR−₩31B−1.3%
  15. 15PharmaResearch−₩28B−4.2%

Retail investors

Net bought

  1. 1Netmarble+₩375B−1.6%
  2. 2Samsung Electronics Pref.+₩325B+1.5%
  3. 3Doosan Enerbility+₩309B−6.5%
  4. 4NAVER+₩164B−4.3%
  5. 5Doosan+₩132B+6.7%
  6. 6Isupetasys+₩108B−5.6%
  7. 7SK Square+₩99B−0.9%
  8. 8Jusung Engineering+₩96B−1.7%
  9. 9KEPCO Engineering & Construction+₩82B−12.0%
  10. 10Korea Electric Power+₩79B−7.1%
  11. 11DB HiTek+₩54B+19.2%
  12. 12Hyundai Motor+₩49B−4.6%
  13. 13L&F+₩47B−7.5%
  14. 14Hyundai Mobis+₩46B−8.8%
  15. 15HD Hyundai Heavy Industries+₩45B−4.0%

Net sold

  1. 1SK hynix−₩2T+2.5%
  2. 2Taihan Fiberoptics−₩157B+29.5%
  3. 3Gaon Cable−₩127B+28.7%
  4. 4Samsung Electro-Mechanics−₩83B−0.9%
  5. 5LIG Defense&Aerospace−₩61B+9.7%
  6. 6Hanmi Pharm−₩55B+8.4%
  7. 7DL E&C−₩52B+1.3%
  8. 8Woori Financial Group−₩47B+2.8%
  9. 9Samsung E&A−₩45B+1.6%
  10. 10Samyang Foods−₩44B+1.7%
  11. 11SFA Semicon−₩43B+28.1%
  12. 12Wonik IPS−₩39B+10.2%
  13. 13LS Electric−₩33B+3.4%
  14. 14LG Energy Solution−₩33B+1.1%
  15. 15Sanil Electric−₩32B+6.5%

ETFs

Best: TIGER Global AI Cybersecurity (+14.3%), SOL Space Aerospace Value Chain (+12.2%), KoAct Optical Communication & Satellite Network Active (+11.5%) and PLUS Aerospace (+11.1%), pointing to space, optical and AI-related funds. Worst: nuclear SMR funds (KODEX Nuclear Power SMR -6.0%, SOL Korea Nuclear SMR -5.7%), Hyundai robotics and auto funds, securities, insurance and shipbuilding funds (-3.2% to -4.6%).

Best ETFs

Worst ETFs

Leveraged and inverse ETFs are left out; moves are the daily moves compounded.

How our signals did

No Squeeze! setups were recorded. Of 33 technical events, 8 worked. Hanyang Digitech's breakout (+26.4%), RaonSecure's breakout (+53.5%) and LS Eco Energy's breakout (+3.4%) worked; The Codi's golden cross (-59.2%), Samhyun's 200-day reclaim (-18.0%) and Iljin Electric's breakout (-22.2%) did not. No pair trades were flagged. Short squeeze scores were 60 for Meritz Financial Group, Hanssem and ISU Specialty Chemical, 58 for SM Entertainment and KMW.

Notable technical signals

33 notable signals: 8 moved the way they pointed so far.

Highest short squeeze scores

Signals describe past prices. Results run from the signal to the latest close; they are not recommendations.

Written by AI from JONBUR's data and checked against those figures. Index and stock moves are the daily moves compounded over the period. Reasons come only from the linked daily wraps, news, filings and broker reports; when none gives a reason, we say so. Not financial advice.

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