Micron’s record results pulled KOSPI back to the 6,900s after a weak open, while KOSDAQ surged more than 4%
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South Korean stocks on October 1 took their cue from Micron’s earnings. The U.S. memory maker reported quarterly revenue of $54.23 billion against expectations of $51.07 billion, and guided next-quarter revenue to about $61.5 billion, also above forecasts. KOSPI rose 1.95% to 6,971.35 and KOSDAQ jumped 4.48% to 894.29. KOSPI opened weak before turning higher in the afternoon, and semiconductor materials, parts and equipment stocks such as Rino Industrial, Wonik IPS and EO Technics posted big gains. Headwinds remain, including high U.S. long-term yields and stalled U.S.-Iran talks.
Micron, often treated as a bellwether for the memory industry, reported quarterly results after the U.S. market closed on September 30. The numbers were strong, yet Micron’s own share price barely moved, and Korean stocks started the day lower. By the afternoon the mood had flipped: KOSPI climbed to within reach of 7,000 and KOSDAQ gained more than 4% in a single session. Here is what Micron reported, how Korean chip stocks reacted, and the variables worth watching.
① The numbers: a beat on nearly every line
Micron’s fiscal fourth-quarter (June–August) revenue came in at $54.23 billion, about 4.8 times the $11.32 billion a year earlier. Adjusted earnings per share were $33.42, and GAAP net income reached $37.7 billion. Compared with consensus compiled by LSEG:
| Item | Actual / Company guidance | Consensus (LSEG) |
|---|---|---|
| Q4 revenue | $54.23 billion | $51.07 billion |
| Q4 adjusted EPS | $33.42 | $31.61 |
| Next-quarter revenue guidance | ~$61.5 billion | ~$57.0 billion |
| Next-quarter adjusted EPS guidance | $38.15 | $35.40 |
Note: consensus figures varied slightly across outlets depending on the data provider.
② The engine: AI data centers and HBM
AI data center demand drove the quarter. Data center–related revenue rose 11-fold from a year earlier, and the core data center business generated roughly $18 billion. By product, DRAM brought in $39.8 billion, or 73% of the total, while NAND contributed $14.1 billion, or 26%.
CEO Sanjay Mehrotra said memory supply and demand should stay tight through 2027 and 2028, and that most of the high-bandwidth memory (HBM) Micron will produce in 2027 is already committed to customers. Micron is viewed as a top-three HBM player behind Samsung Electronics and SK hynix, so its read on the industry matters for Korean memory makers too.
③ A quiet share-price reaction: expectations were already high
The market reaction was muted. Micron shares ended the regular session essentially flat at $1,065.11, and after-hours moves were reported differently by different outlets: a small decline of 0.69% in one, a gain of about 1.6% in another. In Seoul, Samsung Electronics and SK hynix hovered near flat right after the open, and KOSPI slipped into the 6,780s.
One reading is that the results were excellent but expectations were already high. Even so, sentiment improved during the session and the index turned positive.
④ KOSPI: first gain in three sessions, closing at 6,971
KOSPI added 133.31 points, or 1.95%, to close at 6,971.35, snapping three straight declines since the holiday break. The index opened at 6,814.49, recovered the 6,900 level in the afternoon and widened its gains. Samsung Electronics rose 2.79% to 276,000 won and SK hynix gained 3.21% to 1,833,000 won; Samsung Electronics preferred (+4.76%) and Samsung Electro-Mechanics (+3.17%) also advanced.
Institutions were net buyers while individuals and foreign investors were net sellers. Foreign investors had sold for four straight sessions through September 30, when KOSPI fell 0.48%, so their direction remains a key thing to watch after this rebound.
⑤ KOSDAQ +4.48%: chip equipment and parts names ran harder
KOSDAQ rose 38.38 points, or 4.48%, to 894.29, more than double KOSPI’s gain. Advancers outnumbered decliners 1,164 to 490, and foreign investors and institutions were net buyers while individuals were net sellers.
Semiconductor materials, parts and equipment stocks led the way: Rino Industrial rose 10.90%, Wonik IPS 9.13%, EO Technics 8.46%, HPSP 8.32% and Simmtech 6.25%. Large caps such as EcoPro (+5.58%), EcoPro BM (+5.13%), Rainbow Robotics (+5.02%) and Alteogen (+4.13%) also gained.
As an interpretation, Micron’s view that the memory upcycle lasts into 2027–2028 can translate into expectations for capital spending and higher factory utilization, which tends to benefit equipment, parts and inspection suppliers. That is the author’s reading, not a conclusion the news reports stated.
⑥ What could derail the rebound: yields, oil and the won
It was not all good news. On September 30, U.S. stocks fell even though the PCE inflation reading came in below expectations: the Dow slipped 0.86% and the S&P 500 0.25%, while the Nasdaq gained 0.24%, as long-term Treasury yields weighed. Reports said the 10-year yield topped 5.3% intraday, its highest since May 2002, and the 30-year yield rose above 5.6%.
Energy markets remain uneasy. With U.S.-Iran talks stalled, Brent crude futures settled at $103.53 a barrel on September 30. The won closed at 1,358.4 per dollar on October 1, weaker by 5.6 won on the day.
📌 Good to Know
- Strong earnings do not guarantee a rising stock. Micron’s flat reaction shows that names with high expectations can respond only modestly to good results.
- A 4%+ one-day jump also signals volatility. The rebound came right after a run of foreign selling, so it is worth checking whether the buying persists.
- The memory boom outlook is the company’s own forecast. Some observers note that higher memory prices raise costs for electronics makers, so demand and pricing deserve continued attention.
- External variables remain. U.S. long-term yields, oil and the exchange rate can offset chip-sector tailwinds. This post is for information only and is not investment advice.
In short, Micron’s results reinforced the message that the AI memory boom is continuing, and KOSDAQ’s equipment and parts stocks felt that heat most. But long-term yields and oil can still shake markets, so whether this rebound becomes a trend will depend on foreign flows and the data ahead.
References
- Newspim — KOSPI rises 1.95% on Micron tailwind, regains 6,900 (newspim.com)
- Etoday — Chips revive the market: KOSPI rebounds after three sessions, KOSDAQ surges 4% (etoday.co.kr)
- Asia Economy — Micron posts record $54.2 billion quarterly revenue on AI demand (view.asiae.co.kr)
- Global Economic — Micron revenue up about fourfold in surprise beat; outlook also strong (g-enews.com)
- Blockmedia — Micron slips 0.7% after hours despite earnings beat (blockmedia.co.kr)
- Economic Review — Micron says most 2027 HBM volume is contracted (econovill.com)
- Infostock Daily — Micron (MU) revenue quadruples on HBM; memory boom seen lasting (infostockdaily.co.kr)