A banker works in front of multiple monitors in the dealing room of Hana Bank on May 12, 2026 in Seoul, South Korea.
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Wall Street’s technology moves and South Korea’s stock market are becoming increasingly intertwined, as spending on artificial intelligence ties the fortunes of U.S. technology giants and South Korean memory chip makers.
The 60-day correlation between Kospi and Nasdaq 100 It recently rose to around 0.50, its highest level since 2021, according to data provided by Rayliant.
This growing relationship reflects the growing dominance of Samsung Electronics and SK Hynix, which account for more than half of the Kospi index. The two companies are at the center of the AI hardware supply chain, providing memory chips needed for data centers run by US tech giants.
“Since the KOSPI has become a semiconductor index, the correlation has increased,” Rolf Balck, an analyst at Futuram Group, told CNBC in an email.
Samsung and SK Hynix are increasingly relying on spending on the same hyperscalers that drive revenue for U.S. semiconductor and technology companies. According to Bulk, data center demand has increased by more than half this year from last year, when it accounted for about 40% of global DRAM demand, and he expects that share to increase further. DRAM (Dynamic Random Access Memory) is used in AI servers.
This will allow Asian investors to quickly learn about the strength of global AI trade before Wall Street opens.
“Samsung and SK Hynix are the first to show a fluid market reaction to an overnight development that will impact global AI demand,” said Chung In-yoon, founder of Fibonacci Asset Management. “SK Hynix in particular is an important barometer due to its exposure to high-bandwidth memory, one of the most critical components in the AI supply chain.”
Recent transactions illustrate that dynamic. On July 13, the Kospi fell more than 8%, dragged down by SK Hynix’s 15% plunge and record decline. The Nasdaq 100 followed suit, ending the day 1.88% lower. Stocks of tech giants fell on the day. Micron Technology fell 4%, SanDisk fell 12% and Intel closed down 6%.
Peter Kim, head of global investment strategy at KB Financial Group, said the rally in Korean memory chips started later than the Nasdaq’s rally as U.S. investors initially focused on hyperscalers. However, the scale and volatility of recent stock gains have led global investors to treat South Korea as a bellwether for broader AI trading.
Samsung’s earnings outlook could also provide one of the first concrete quarterly signals on the state of AI demand. The company typically releases its results about two weeks before major U.S. semiconductor companies.
However, analysts cautioned that South Korean and U.S. technology stocks are moving in tandem, with one not always leading the other.
“The fate of U.S. tech stocks and Korean tech stocks is increasingly driven by a common underlying factor: sentiment towards AI hardware trading,” said Philip Uhl, head of research at Rayliant Global Advisors.
If AI-related news breaks while U.S. markets are closed, Samsung and SK Hynix could serve as a proxy for how investors will react when Wall Street reopens. As developments occur during US trading, Nasdaq provides a preview of upcoming Korean trading as well.
Close relationships also come with risks. Industry veterans echoed similar sentiments, saying rising correlations undermine the diversification benefits investors traditionally seek from owning U.S. and Korean stocks.
“South Korea no longer offers diversification against US technology. With half of the index tied to one cyclical theme, a slowdown in hyperscaler capex will hit the Korean market harder than most other markets,” Baruch said.
He also added that Korean memory stocks are inherently more volatile than many U.S. chip makers, with volatility amplified by leveraged exchange-traded fund flows.
Wool similarly highlighted that as the AI theme becomes a major driver for South Korean and US technology stocks, investors are losing geographic diversification, one of the main reasons for owning both markets.
“If all these markets are essentially driven by this one big risk factor, you find yourself missing out on the very benefits of international diversification that led you to seek exposure to geographically disparate markets like the U.S. and South Korea in the first place.”
However, large discrepancies can occur over time. micronSamsung and SK Hynix are currently benefiting from similar DRAM price increases, but differences in capital investment, product mix and U.S. support for domestic chip production could ultimately lead to divergent results, Kim said.
China’s expansion into memory chips also poses new risks, he added. Although Chinese producers still lag behind global rivals technologically, their progress has often exceeded investors’ expectations. Shares of semiconductor maker Changxin Science and Technology Group soared 466% on Monday on its listing on Shanghai’s tech-heavy STAR market, making CXMT China’s most valuable listed company.
