South Korea’s benchmark KOSPI index tested support levels today, closing 4.52% lower at 7,730.82 as a sharp repricing of the global AI semiconductor trade triggered selling in the market’s two largest constituents.
The KOSPI tested critical support around 7,500 during intraday trading, hitting a session low of 7,541.11 before dip-buyers emerged into the close. The index has now fallen 10.36% over the past week, again following the semiconductor trend, such is the weight of the leading names.
Samsung Electronics shares tumbled 6.06% on the day, while SK Hynix dropped 7.54% to close at 2,048,000 won after briefly losing the psychologically important 2,000,000 won level during the session. The magnitude of the decline in these two names mechanically amplified the index move, given their outsized weighting in the KOSPI’s market cap structure.
The selloff in Seoul mirrored weakness across global semiconductor markets. The Global X Semiconductor ETF (ASX:SEMI), a widely-followed proxy chip leaders, traded 4.40% lower today and has fallen 7.51% over the previous five trading days. Despite the recent pullback in the sector, the ETF remains 69.81% higher YTD, with other leading funds such as the VanEck Semiconductor ETF (SMH) 58.32% higher YTD and has doubled over the past twelve months, underscoring the magnitude of the AI-driven rally that preceded this correction.
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Core Details
Today’s decline represents the culmination of a week-long unraveling of what had been one of the year’s most crowded trades. Earlier this week, the KOSPI experienced extraordinary volatility, plunging 8% within minutes of the open on June 8 and briefly triggering circuit breakers before staging an 8% recovery the following day.
The concentration risk inherent in the KOSPI’s structure has become painfully apparent. Samsung Electronics and SK Hynix together represent ~50% of the index’s total market cap, effectively transforming South Korea’s benchmark into a leveraged bet on global AI memory and logic chip demand rather than a broad domestic economy proxy. When sentiment shifts in the semiconductor sector, the KOSPI moves in lockstep, and often with amplified volatility.
Foreign investors have been consistent net sellers across recent sessions, offloading hundreds of billions of won in KOSPI stocks and exacerbating the index decline. Meanwhile, retail investors have attempted to buy the dip, particularly in Samsung and SK Hynix shares, viewing the crashes as potential entry points into the long-term AI boom. This dynamic has created violent intraday swings as domestic buying temporarily pushes the index higher before renewed foreign selling resumes.
Domestic policy noise has also unsettled markets. In recent weeks, a senior Korean policymaker floated using additional tax revenue from semiconductor and AI profits to fund a form of “national dividend” sparking debate and briefly pushing the KOSPI down over 5% in a single day as markets worried about policy risk to chipmakers’ margins and capital allocation. Subsequent clarifications stressed that any such program would use surplus tax receipts rather than impose new levies directly on firms, calming some of those fears, but the episode highlighted the political sensitivity around the sector’s outsized profits.
Outlook
The question now facing markets is whether this represents a violent but ultimately healthy correction within a secular AI uptrend, or the beginning of a more sustained de-rating of stretched semiconductor valuations. Samsung Electronics, and SK Hynix, have both performed up there with the best Asia listed tech stocks in recent times, and their weight on the index has increased as result.
Bears point to several concerning signals. Valuations for Korean chipmakers have expanded significantly alongside global peers like Nvidia and TSMC, feeding concerns that earnings expectations could prove too optimistic if the AI capital expenditure boom slows.
Bulls, however, maintain that the fundamental AI semiconductor thesis remains intact. The KOSPI had undergone a parabolic move higher in recent months, with several brokerage houses lifting index targets as recently as mid-May. Some degree of profit-taking was inevitable after such a strong run. Earnings visibility for leading AI memory and logic producers remains robust into 2027, and overcapacity risk appears years away rather than imminent.
The defense of the 7,500-7,550 support area during today’s intraday trading and the last-minute bid into the close demonstrate that dip-buyers remain active. For now, the KOSPI remains caught between the powerful secular tailwinds of artificial intelligence and the painful reality that even the strongest fundamental stories can experience sharp corrections when sentiment shifts and crowded trades unwind.
