Korea's AI stocks now set the tone for global markets

South Korea's $4 trillion（約640兆円） equity market has unexpectedly become the heartbeat of global AI and semiconductor investment, reshaping trading routines for fund managers across London, New York, and Tokyo. The shift centers on two chip manufacturers—SK Hynix Inc. and Samsung Electronics Co.—that supply critical memory components for AI systems worldwide. Once a peripheral market for many global investors, Korea now offers an early read on investor appetite for AI assets each trading day.

The tightening linkage is measurable: the 60-day correlation between the Kospi Index and the Nasdaq 100 has climbed to 0.46, nearly triple its five-year average of 0.16, according to Bloomberg data cited in the article. When the Kospi suffers weakness, the effect on US markets intensifies. The Nasdaq 100 Index's sensitivity to the Kospi during Korean market downturns reached its highest level since 1990 on July 7. SK Hynix's recent listing on Wall Street has extended Korea's influence directly into US trading, allowing portfolio managers to track Korean sentiment through the company's American depositary receipts and Korea-focused exchange-traded funds. One London-based portfolio manager at PineBridge Investments, Hani Redha, described the dynamic as "almost 24-hour tracking"—following Seoul's market close, he shifts focus to SK Hynix's US shares and Korea-focused ETFs in New York.

The market's growing prominence is reflected in how investment institutions are reshaping their operations. JPMorgan Asset Management's chief Asia market strategist presented Korea to the firm's global team for the first time in his 14 years on the job. Japanese traders have added the Kospi to their watch lists. Andrew Jackson, head of Japan equity strategy at Ortus Advisors, added a chart of the Kospi for close monitoring earlier this year—a first in more than two decades. Ivan Feinseth, chief investment officer at Tigress Financial Partners in New York, stated that "Korea has effectively become part of the same volatility ecosystem as the Nasdaq and SOX, with SK Hynix, Samsung and the Kospi now functioning as a pre-market read-through on US AI and semiconductor risk."

The risks, however, are substantial. The Kospi has become one of the world's most volatile major benchmarks, with leveraged trading amplifying swings. Last week, a local selloff driven by fresh skepticism about future AI demand triggered a near 9% drop in the Kospi, before weakness spilled into Wall Street. SK Hynix's US-listed shares dropped 9.3%, dragging down other major chip stocks. The Kospi has tumbled 25% since its June peak, resulting in a $1 trillion（約160兆円） wipeout that threatens to weaken its global clout; its chipmaker duo have both lost at least 30% of their value. South Korea's decision to temporarily halt new listings of single-stock leveraged exchange-traded products may help curb speculation and volatility. Despite the decline, the benchmark remains up 62% for the year, among the world's best performers, and given the pivotal role of SK Hynix and Samsung in memory chip supply, the Korean market will likely remain the heartbeat of global AI investment in the foreseeable future. Chisa Kobayashi, Japan equity strategist at UBS SuMi TRUST Wealth Management, noted that the dominance of a relatively immature market with leverage-related swings "makes trading difficult because moves can deviate from fundamentals."

South Korea's equity market, long viewed by global investors as a peripheral emerging market, has undergone a structural shift in its role within the global financial system. The transformation is rooted in the concentration of two companies—SK Hynix and Samsung Electronics—that control outsized shares of the memory chip supply critical to AI infrastructure. As AI investment has become the dominant theme driving equity markets worldwide, Korea's market has moved from the periphery to the center of daily trading decisions in London, New York, and Tokyo.

This shift is visible in the correlation metrics the body cites: the 60-day correlation between the Kospi and the Nasdaq 100 has reached 0.46, nearly three times the five-year average of 0.16. For portfolio managers, the practical implication is substantial. A Korean selloff no longer stays contained in Seoul—it extends immediately into Wall Street through SK Hynix's US listing and ripples across global chip stocks. The article quotes a London-based manager at PineBridge Investments saying "We are all Korean investors now," reflecting a genuine reordering of investment priorities.

However, the body notes that Korea's growing influence carries a structural weakness: the Kospi has become one of the world's most volatile major benchmarks, amplified by leveraged trading products. The recent 25% decline from the June peak—erasing $1 trillion（約160兆円） in value—demonstrates both the market's sensitivity to sentiment swings and the risk that excessive leverage can disconnect price movements from fundamentals. Even as SK Hynix and Samsung's pivotal role in chip supply suggests Korea will remain central to global AI investment, the volatility driven by leverage-fueled trading is creating friction for fund managers trying to distinguish genuine risk shifts from technical excess.