KOSPI surges 4.89% to 8,885 as Micron earnings fuel chip rally
Synopsis
Micron Technology's blowout quarterly earnings did more than lift a US stock — they ignited Seoul's entire chip complex. With SK Hynix up nearly 10% and KOSPI adding almost 5% in a single session, South Korea's market is signalling that the AI memory upcycle is very much alive, even as Wall Street wobbled on valuation fears the night before.
Key Takeaways
KOSPI surged 414.55 points (4.89%) to 8,885.57 as of 11:20 am on 25 June .
Micron Technology 's better-than-expected quarterly earnings were the primary catalyst, easing AI demand concerns.
SK Hynix soared 9.61% and Samsung Electronics jumped 4.77% , leading blue-chip gains.
South Korea's stock trading accounts hit a record 108.7 million , up more than 10 million since end of last year, per KOFIA data.
The KOSPI had already crossed 9,000 points for the first time this month on AI optimism.
The Korean won weakened slightly to 1,547.25 per US dollar, down 5.25 won from the prior session.
South Korea's benchmark Korea Composite Stock Price Index (KOSPI) extended sharp gains on Thursday, 25 June, climbing 414.55 points, or 4.89 percent, to 8,885.57 as of 11:20 am local time, powered by a semiconductor rally after Micron Technology posted quarterly earnings that significantly beat market expectations. The results effectively dispelled near-term concerns over the pace of artificial intelligence (AI) demand growth.
What Triggered the Rally
Micron Technology, the world's third-largest memory chipmaker, released its quarterly results after Wall Street's close on Wednesday. The earnings sharply exceeded analyst forecasts, reversing overnight caution on US markets, where indices had closed mixed amid worries about AI-related share overvaluation. Seoul's market opened 2.74 percent higher and extended those gains through the morning session.
Blue Chips Lead the Charge
Market bellwether Samsung Electronics jumped 4.77 percent, while chip giant SK Hynix soared 9.61 percent, underscoring the outsized impact of Micron's results on South Korean semiconductor names. Hanmi Semiconductor, a leading chip equipment maker, advanced 2.22 percent, and LG Electronics rose 0.24 percent. Financial stocks also participated in the broader rally, with KB Financial Group gaining 1.91 percent and Samsung Life Insurance climbing 6.47 percent.
Won Edges Lower Against Dollar
The Korean won was trading at 1,547.25 won per US dollar as of 11:20 am, down 5.25 won from the previous session, reflecting modest currency pressure even as equities surged. Currency softness alongside an equity rally is a pattern often seen when foreign institutional flows chase stocks but hedge currency exposure.
Record Trading Accounts Signal Retail Surge
The rally arrives against a backdrop of surging retail participation. The number of stock trading accounts in South Korea reached a record 108.7 million as of Wednesday, up more than 10 million from 98.28 million at the end of last year, according to data from the Korea Financial Investment Association (KOFIA). That compares with an increase of 11.7 million accounts through all of last year, suggesting this year's pace of retail entry is already tracking ahead. The influx has been driven largely by retail investors buying heavyweight names such as Samsung Electronics and SK Hynix. Notably, the KOSPI surpassed the 9,000-point mark for the first time this month, riding AI-driven technology optimism.
What to Watch Next
The sustainability of the rally will depend on whether AI spending by major US hyperscalers holds up in coming quarters and whether Micron's earnings signal a broader memory upcycle. Any renewed caution from the US Federal Reserve or a softening in AI capital expenditure guidance from big tech could quickly reverse sentiment in Seoul's chip-heavy index.
Point of View
Seoul could give back these gains just as violently as it captured them.
NationPress
25 Jun 2026
Frequently Asked Questions
Why did the KOSPI surge on 25 June?
The KOSPI surged 4.89% to 8,885.57 on 25 June after Micron Technology released quarterly earnings that sharply beat market expectations, easing concerns about slowing AI demand. South Korean chipmakers Samsung Electronics and SK Hynix led the rally as direct beneficiaries of a memory upcycle.
How much did Samsung Electronics and SK Hynix gain?
Samsung Electronics jumped 4.77% and SK Hynix soared 9.61% during the morning session on 25 June. Both stocks were the primary drivers of the KOSPI's broad-based advance.
What is the significance of South Korea's record trading accounts?
Stock trading accounts in South Korea reached a record 108.7 million as of Wednesday, up more than 10 million from 98.28 million at the end of last year, according to KOFIA data. The surge reflects growing retail investor participation, concentrated in heavyweight chip stocks, and mirrors the KOSPI's climb past 9,000 points for the first time this month.
How did Wall Street perform before Seoul's rally?
Wall Street closed mixed on Wednesday amid concerns about the overvaluation of AI-related shares. Micron Technology's earnings, released after the US market close, reversed that caution and set the stage for Seoul's sharp open the following morning.
What could slow down the KOSPI rally?
Analysts caution that the rally's durability hinges on continued AI capital expenditure by major US technology companies. Any softening in AI spending guidance or renewed US Federal Reserve hawkishness could quickly dampen sentiment in Seoul's chip-heavy index.
