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Monthly wrap · May 2026 · 18 trading days

KOSPI rises 28.5% in May to a record 8,476.2 on memory chips; KOSDAQ falls 9.9% as bio stocks slump

KOSPI+28.5%KOSDAQ−9.9%KOSPI 200+35.4%

The KOSPI closed May at a record 8,476.15, up 28.5% over the period, while the KOSDAQ fell 9.9% to 1,074.8 and the KOSPI 200 rose 35.4% to 1,342.82. Memory chips led. Sources cite tight supply of high-end memory used in AI chipsets, Samsung Electronics' HBM4E sample shipment and anticipation of Nvidia CEO Jensen Huang's visit to Korea. SK hynix rose 81.4% and Samsung Electronics rose 43.8%. Samsung Electronics passed $1 trillion in market value on May 6 and SK hynix later joined the club, according to one report.

A second chain ran through AI server components. Samsung Electro-Mechanics rose 155.7%, LG Innotek 154.5% and Samwha Capacitor 121.9%, on expected MLCC price increases, a large silicon capacitor supply deal with a North American big tech firm and AI data center demand. Brokers raised target prices. Samsung Electro-Mechanics passed ₩100 trillion in market value. On May 21 the KOSPI jumped 8.42% after Samsung Electronics and its union reached a tentative deal that avoided a strike and a halt to chip lines. Earlier, the US 10-year yield closed at 4.595%, the highest since July 2007, on oil gains tied to the Middle East war, and the KOSPI hit two sell sidecars. Bio stocks fell sharply, pulling the KOSDAQ lower.

Why the market moved

The KOSPI rose on tight high-end memory supply, Samsung's HBM4E sample shipment, the tentative Samsung union deal and hopes for US-Iran talks, despite a mid-month rate-driven sell-off.1234

Top themes

AI server components (MLCC)

MLCC price hikes, silicon capacitor supply deal123

Memory chips

Tight high-end memory supply, HBM4E sample12

The big stories

MLCC makers surge on AI server demand and price hikes

Samsung Electro-Mechanics, LG Innotek and Samwha Capacitor rallied on expectations of MLCC price increases, a large silicon capacitor supply deal with a North American big tech firm, and AI data center demand, with Samsung Electro-Mechanics passing 100 trillion won in market value. Closing moves over the period were +155.67% for Samsung Electro-Mechanics, +154.45% for LG Innotek and +121.86% for Samwha Capacitor.1234567891011

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Further out

Kospi hits record 8,476 as memory chip makers lead the rally

The Kospi closed at a record 8,476.15 on May 29 as SK hynix and Samsung Electronics led gains on tight high-end memory supply, Samsung's HBM4E sample shipment and anticipation of Nvidia CEO Jensen Huang's visit to Korea. Closing moves over the period were +28.45% for the Kospi, +81.41% for SK hynix and +43.76% for Samsung Electronics.123456

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Samsung union reaches tentative deal, averting chip line halt

Samsung Electronics and its union reached a tentative agreement on performance pay after mediation by the labor minister, so chip production lines did not stop, and the Kospi jumped 8.42% in a single session on May 21. The rally was led by electronics, transport equipment and machinery shares.12

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Bio stocks slump drags Kosdaq; Kosdaq down 9.86% over the period

Bio stocks fell sharply as rising US and global bond yields hit growth shares, with Kosdaq falling to 1,056.07 on May 20 and bio names down about 15% while the index was up 10%. Closing moves over the period were -9.86% for the Kosdaq, -55.84% for Medipostco and -50.79% for Huons Global, which was linked to a merger decision.123456789

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Further out

US 10-year yield tops 4.5%, triggering Kospi sidecar

The US 10-year Treasury yield closed at 4.595% on May 15, its highest since July 2007, as Middle East war-driven oil gains raised inflation fears, and the Kospi fell to 7,142.71 intraday on May 18 with two sell sidecars. The Kospi closed at 7,208.95 on May 20, down 0.86%, on foreign selling of electronics shares.123

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Further out

The market

The KOSPI rose 28.5% to 8,476.15, the KOSDAQ fell 9.9% to 1,074.8 and the KOSPI 200 rose 35.4% to 1,342.82. Breadth was weak beneath the index: 515 stocks rose, 2,081 fell and 175 were unchanged. Trading value was about ₩92.5 trillion against an average of about ₩64.1 trillion. On May 21 the KOSPI rose 8.42%, a record 606-point gain, helped by Nvidia's results and hopes for US-Iran peace talks that eased oil and global bond yields. On May 29 the KOSPI rose 3.55%, or 290.86 points. The won weakened 2.0% to ₩1,505.8 per dollar and the 3-year KTB yield was 3.731%, up 13.6 basis points. Foreign investors net sold about ₩44.7 trillion on the KOSPI and net bought about ₩2.8 trillion on the KOSDAQ.

KOSPIDaily closes · shaded: this wrap8,476.15
4,0006,0008,000
Oct 27Jan 6Mar 19May 29
KOSDAQDaily closes · shaded: this wrap1,074.8
9001,0001,1001,200
Oct 27Jan 6Mar 19May 29

515 stocks rose, 2,081 fell · trading value ₩92T

USD/KRW1,505.8+2.0%
KTB 3y3.73+14bp

Themes investors follow

HBM & AI chips rose 19.7%, led by SK hynix (+81.4%), Samsung Electronics (+43.8%) and HVM (+23.4%), while Hanmi Semiconductor fell 23.4%. Self-driving rose 26.7% on Hyundai Mobis (+80.7%). Chip testing and packaging rose 9.9%, with Mirae +139.5% and Jeju Semiconductor +86.6%. Smartphone parts rose 4.1%, led by Samsung Electro-Mechanics and LG Innotek. Hydrogen rose 4.8% on Doosan Fuel Cell (+50.3%). AI software and services fell 9.9% overall, though Samsung SDS rose 79.9%. Semiconductor equipment fell 5.8% despite Fidelix (+329.3%) and Samt (+121.3%).

The weakest themes were crypto (-32.4%), solar and wind (-27.3%), AI healthcare (-25.5%), K-drama (-23.7%), K-defense (-21.4%), shipbuilding (-21.3%), leisure (-21.2%) and REITs (-19.9%). Biotech fell 15.1%. Reports linked the bio slump to higher bond yields hitting growth shares; one analysis also pointed to new single-stock leveraged ETFs on Samsung Electronics and SK hynix. Medipostco fell 55.8% despite positive Japan phase 3 results, which the market reportedly had priced in. Huons Global fell 50.8%, linked to a merger decision. Curocell fell 45.7%, ToolGen 42.4%.

Popular themes

Best themes

  • Self-driving+26.7%Hyundai Mobis +80.7% · HL Mando +8.8% · Nextchip −9.4%
  • HBM & AI chips+19.7%SK hynix +81.4% · Samsung Electronics +43.8% · HVM +23.4%
  • Chip testing & packaging+9.9%Mirae +139.5% · Jeju Semiconductor +86.6% · Simmtech Holdings +43.1%
  • Hydrogen+4.8%Doosan Fuel Cell +50.3% · Doosan Fuel Cell Pref. +3.5% · Doosan Fuel Cell 2nd Pref. −5.6%
  • Smartphone parts+4.1%Samsung Electro-Mechanics +155.7% · LG Innotek +154.5% · Samsung Electro-Mechanics Pref. +119.8%
  • Insurance+1.2%Samsung Life Insurance +55.7% · Samsung Fire & Marine Insurance +23.4% · Hyundaimarine&Fireinsuranceco +13.7%

Worst themes

  • Crypto & digital assets−32.4%Satoshi Holdings −38.5% · Parataxis Ethereum −32.8% · GalaxiaMoneytree −26.1%
  • Solar & wind−27.3%S-Energy −33.8% · CS Wind −33.7% · SK eternix −30.9%
  • AI healthcare−25.5%Vuno −52.7% · Noul −37.0% · Synteka Bio −31.9%
  • K-drama & film−23.7%Dexter studios −43.8% · Studio Mir −36.8% · Keyeast −34.2%
  • K-defense−21.4%SolDefense −37.6% · Samyang Comtech −35.0% · Victek −34.0%
  • Shipbuilding−21.3%STX Engine −34.4% · IL Seung −33.0% · HD-Hyundai Marine Engine −32.8%

The biggest companies

Samsung Electronics (₩1,853.3 trillion) rose 43.8% and SK hynix (₩1,662.7 trillion) rose 81.4%, on the memory rally. SK Square rose 46.6%, Samsung Electro-Mechanics 155.7%, Hyundai Motor 36.1%, Samsung Life Insurance 55.7%, Samsung C&T 44.9% and Hyundai Mobis 80.7%; no clear reason was reported for the moves in the last four. KIA rose 11.5% and HD Hyundai Heavy Industries 1.6%. LG Energy Solution slipped 0.5%. Doosan Enerbility fell 16.9%, Hanwha Aerospace 17.2%, Samsung Biologics 7.3% and KB Financial Group 6.2%.

Who was buying and selling

Foreign investors were heavy net sellers of the leaders: SK hynix (about ₩20.7 trillion), Samsung Electronics (about ₩16.0 trillion), Hyundai Mobis (about ₩2.6 trillion), SK Square (about ₩1.4 trillion) and Hyundai Motor (about ₩1.3 trillion). Their top buys were Doosan Robotics (about ₩657.6 billion), Samsung SDI (about ₩507.4 billion) and Fadu (about ₩437.4 billion, +43.4%). Institutions bought Samsung Electronics (about ₩6.2 trillion), SK hynix (about ₩4.6 trillion) and SK Square (about ₩1.2 trillion). Retail investors bought SK hynix (about ₩15.9 trillion) and Samsung Electronics (about ₩9.6 trillion), plus Hyundai Mobis, Doosan Enerbility and Samsung Heavy Industries, which fell 16.9% and 13.6%. On May 29 retail and foreign investors net sold ₩1.4 trillion and ₩1.1 trillion on the KOSPI while institutions bought ₩2.4 trillion.

Foreign investors

Net bought

  1. 1Doosan Robotics+₩658B−3.4%
  2. 2Samsung SDI+₩507B−1.0%
  3. 3Fadu+₩437B+43.4%
  4. 4Hyundai Engineering & Construction+₩293B−9.2%
  5. 5LG Display+₩238B+31.2%
  6. 6Doosan+₩196B+23.6%
  7. 7KT&G+₩191B+3.6%
  8. 8Samsung Fire & Marine Insurance+₩186B+23.4%
  9. 9POSCO Holdings+₩174B−8.4%
  10. 10LG Energy Solution+₩161B−0.5%
  11. 11Krafton+₩160B−2.8%
  12. 12Ecopro BM+₩155B+5.3%
  13. 13SK+₩148B+59.1%
  14. 14Hanon Systems+₩131B+33.1%
  15. 15ABL Bio+₩125B−17.0%

Net sold

  1. 1SK hynix−₩21T+81.4%
  2. 2Samsung Electronics−₩16T+43.8%
  3. 3Hyundai Mobis−₩2.6T+80.7%
  4. 4SK Square−₩1.4T+46.6%
  5. 5Hyundai Motor−₩1.3T+36.1%
  6. 6LG Innotek−₩968B+154.5%
  7. 7LG Electronics−₩630B+108.0%
  8. 8Samsung Heavy Industries−₩605B−13.6%
  9. 9Hanmi Semiconductor−₩581B−23.4%
  10. 10LS Electric−₩571B−13.1%
  11. 11Samsung Electro-Mechanics−₩546B+155.7%
  12. 12Doosan Enerbility−₩474B−16.9%
  13. 13Isupetasys−₩400B−14.0%
  14. 14Jusung Engineering−₩354B+58.7%
  15. 15Hyundai Glovis−₩346B+6.8%

Institutions

Net bought

  1. 1Samsung Electronics+₩6.2T+43.8%
  2. 2SK hynix+₩4.6T+81.4%
  3. 3SK Square+₩1.2T+46.6%
  4. 4Hyundai Mobis+₩931B+80.7%
  5. 5Hyundai Motor+₩693B+36.1%
  6. 6Samsung Electro-Mechanics+₩577B+155.7%
  7. 7LG Innotek+₩425B+154.5%
  8. 8LG Electronics+₩393B+108.0%
  9. 9Samsung Life Insurance+₩242B+55.7%
  10. 10Samsung C&T+₩200B+44.9%
  11. 11Korea Aerospace Industries+₩172B−0.4%
  12. 12Hyundai Glovis+₩168B+6.8%
  13. 13Hyundai Autoever+₩156B+106.7%
  14. 14Tesco+₩140B+41.8%
  15. 15Alteogen+₩123B+0.1%

Net sold

  1. 1Doosan Robotics−₩519B−3.4%
  2. 2Doosan Enerbility−₩427B−16.9%
  3. 3SKC−₩300B+18.1%
  4. 4Samsung Biologics−₩238B−7.3%
  5. 5Mirae Asset Securities−₩232B−5.3%
  6. 6Hyundai-Rotem−₩224B−25.3%
  7. 7Samsung Heavy Industries−₩218B−13.6%
  8. 8Fadu−₩211B+43.4%
  9. 9Hyosung Heavy Industries−₩207B−5.8%
  10. 10Hanwha Aerospace−₩203B−17.2%
  11. 11LS Electric−₩198B−13.1%
  12. 12Doosan−₩190B+23.6%
  13. 13Samsung SDI−₩180B−1.0%
  14. 14L&F−₩176B−13.7%
  15. 15Leeno Industrial−₩169B−18.4%

Retail investors

Net bought

  1. 1SK hynix+₩16T+81.4%
  2. 2Samsung Electronics+₩9.6T+43.8%
  3. 3Hyundai Mobis+₩1.4T+80.7%
  4. 4Doosan Enerbility+₩888B−16.9%
  5. 5Samsung Heavy Industries+₩799B−13.6%
  6. 6LS Electric+₩756B−13.1%
  7. 7Hanmi Semiconductor+₩666B−23.4%
  8. 8Hyundai Motor+₩566B+36.1%
  9. 9LG Innotek+₩537B+154.5%
  10. 10Jusung Engineering+₩509B+58.7%
  11. 11Hyosung Heavy Industries+₩474B−5.8%
  12. 12Mirae Asset Securities+₩445B−5.3%
  13. 13Isupetasys+₩351B−14.0%
  14. 14Samsung Securities+₩301B+11.4%
  15. 15Hanwha Ocean+₩284B−6.4%

Net sold

  1. 1Samsung SDI−₩310B−1.0%
  2. 2SK−₩249B+59.1%
  3. 3Samsung C&T−₩239B+44.9%
  4. 4LG Display−₩229B+31.2%
  5. 5Fadu−₩212B+43.4%
  6. 6Hyundai Engineering & Construction−₩158B−9.2%
  7. 7Taihan Cable & Solution−₩158B−19.3%
  8. 8Samsung Fire & Marine Insurance−₩148B+23.4%
  9. 9LG CNS−₩147B+75.0%
  10. 10Rainbow Robotics−₩142B+5.7%
  11. 11Simmtech−₩135B+35.8%
  12. 12Korean Air Lines−₩129B+9.1%
  13. 13Doosan Fuel Cell−₩129B+50.3%
  14. 14Alteogen−₩129B+0.1%
  15. 15LIG Defense&Aerospace−₩129B−14.9%

ETFs

The best ETFs were technology and AI-chip funds: TIGER US Space Tech (+87.7%), RISE Network Infrastructure (+82.3%), IBK K-AI Semiconductor Core Tech (+79.9%), SOL AI Semiconductor TOP2 Plus (+76.1%) and SOL Auto Parts & Materials Fn (+71.9%). KODEX 200 IT TR rose 65.6%. The worst were SOL Shipbuilding Equipment (-28.0%), PLUS K-Defense Parts & Materials (-25.0%), TIGER Media Contents (-23.0%), TIGER Korea Nuclear Power (-20.6%) and SOL Korea Nuclear SMR (-20.6%). KODEX WTI Crude Oil Futures (H) fell 17.2%. Gains concentrated in chips and autos, while defense, shipbuilding, nuclear and media funds fell.

Best ETFs

Worst ETFs

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

How our signals did

No Squeeze! setups, technical events or pair trades were recorded since May 4. Short squeeze scores were highest for Meritz Financial Group (60, from 55), Hanssem (60, from 47) and ISU Specialty Chemical (60, from 52), followed by SM Entertainment (58, from 53) and KMW (58, from 60). Three IPOs listed in May: Cosmo Robotics (May 11), Poled (May 14) and MakinaRocks (May 20).

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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