Fund managers in London, New York, and Tokyo have added a new step to their morning routine: checking South Korean stocks. Korea’s $4 trillion equity market is now offering an early read on global AI risk appetite, as swings in SK Hynix and Samsung ripple through chip stocks worldwide. PineBridge Investments portfolio manager Hani Redha explained the new reality: “We are all Korean investors now.” For JPMorgan Asset Management’s chief Asia market strategist, presenting on Korea to the firm’s global team was a first in his 14-year career.
The deepening correlation between Kospi and Nasdaq
The data confirms the shift. The 60-day correlation between the Kospi and the Nasdaq 100 has climbed to 0.46, near the highest in two years and almost triple its five-year average of 0.16. This linkage intensifies during selloffs: the Nasdaq 100’s sensitivity to the Kospi during periods of Korean market weakness hit its highest level since 1990 on July 7. SK Hynix’s entry into the trillion-dollar club earlier this year, combined with its US-listed shares, now extends Korea’s influence into Wall Street trading hours. Redha tracks Seoul first, then SK Hynix’s ADRs, then Korea-focused ETFs in New York. “It’s like almost 24-hour tracking,” he said.
The cost of influence: volatility and retail leverage
The influence comes with a cost. The Kospi has become one of the world’s most volatile major benchmarks, with leveraged single-stock products amplifying swings. A Monday selloff driven by scepticism about AI demand triggered a near 9% Kospi drop that spilled into Wall Street, dragging SK Hynix’s US shares down 9.3%. The Kospi has tumbled 25% since its June peak, wiping out $1 trillion in market value. South Korea temporarily halted new listings of single-stock leveraged ETFs to curb speculation.
Korea’s semiconductor dominance
Despite the volatility, the benchmark is still up 62% for the year. South Korea committed $880 billion over a decade to chips, AI data centres, and robots. Samsung and SK Hynix control the majority of global memory chip supply, particularly high-bandwidth memory (HBM) critical for AI accelerators. As long as that supply bottleneck holds, Korea’s sentiment-driven trading will continue to set the tone for every AI stock that depends on it. Chisa Kobayashi at UBS noted: “This is the new normal investors have to accept, as long as the AI rally continues.” The question remains whether a market driven by retail leverage in Seoul should be the one telling London what to think about AI.
Historical context: Korea’s rise in the global chip market
South Korea’s semiconductor industry has been a powerhouse for decades. Samsung Electronics became the world’s largest memory chip maker in the early 2000s, and SK Hynix transformed from a former Hyundai division into a leading supplier of DRAM and NAND flash. The AI boom drove unprecedented demand for HBM, which SK Hynix pioneered in partnership with Nvidia. By 2024, SK Hynix supplied over 90% of HBM3 chips used by Nvidia. Samsung followed closely with its own HBM3E. This dominance made Korean stocks a proxy for AI hardware demand.
The global ripple effect
Korean stocks now affect AI-related companies worldwide. When SK Hynix reports earnings or adjusts guidance, it moves shares of Nvidia, AMD, Micron, and even cloud providers like Amazon and Microsoft. A strong Korean won can signal confidence in chip demand, while a weak won raises concerns about export competitiveness. The Korean circuit breaker—a 8-10% drop triggers a 20-minute halt—has become a global event. For example, on August 5, a 8.8% Kospi drop halted trading, only to resume and stabilise after news of Samsung’s new HBM deal. That same day, the Philadelphia Semiconductor Index fell 4%, with SK Hynix’s ADRs losing 9%.
Retail investor frenzy and regulatory response
Korea’s retail investors have fuelled the volatility. The number of Korean retail accounts surged from 6 million in 2019 to over 14 million by 2024. Many used leveraged ETFs to magnify gains, with daily trading volumes exceeding $20 billion. The government’s decision to halt new listings of single-stock leveraged ETFs did little to calm markets, as existing products continued to amplify moves. Analysts estimate that retail investors now hold over 30% of SK Hynix’s local shares. Their sentiment swings, often driven by social media and news headlines, create sharp movements that spill over to global exchanges.
Future outlook: will the correlation persist?
The question now is whether Korea’s role will diminish as AI hardware becomes more commoditised or if new competitors like TSMC and Intel gain ground. TSMC’s dominance in logic chips and advanced packaging contrasts with Korea’s strength in memory. However, the rise of AI requires both compute and memory, so Korea remains essential. If the AI rally continues, Korea’s leverage-reliant market may continue to set the global tone. If it falters, the unwinding could be even more dramatic. As UBS’s Kobayashi says, “Investors must live with this new normal.” For now, global fund managers cannot ignore the opening bell in Seoul.
Key facts at a glance
- Kospi-Nasdaq 100 60-day correlation: 0.46 (triple the five-year average of 0.16).
- SK Hynix market cap surpassed $1 trillion in 2024.
- South Korea allocated $880 billion over 10 years for chips, AI, and robots.
- Samsung and SK Hynix control over 70% of global memory chip supply.
- Kospi dropped 25% from its June peak, losing $1 trillion.
- South Korea temporarily banned new single-stock leveraged ETFs to curb speculation.
- PineBridge Investments and JPMorgan Asset Management now track Korean markets as a global lead indicator.