The bottom line: Korean stocks and the US Nasdaq now move almost as a single trade. Kobeissi flags a structural shift in how Korean and US equities move together. The 60-day correlation between the KOSPI and the Nasdaq 100 has climbed to +0.46, the highest reading since July 2024, a sharp reversal from -0.20 back in March. That's roughly three times the five-year average of +0.16. The relationship isn't just tighter, it's asymmetric in a telling way: the Nasdaq 100's sensitivity to declines in Korean stocks is at its highest since 1990, and the MSCI World Index's sensitivity to the Korean market is at a four-year high. In plain terms, when Korean equities sell off now, it's increasingly read as an early warning for risk appetite in US and global tech, not the other way around. That tracks with how central SK Hynix and Samsung have become to the AI hardware supply chain this year, memory names that Wall Street watches for signs of whether AI capex demand is real or cracking. The takeaway for anyone holding both US tech and Korean chip stocks: the diversification benefit of spreading a portfolio across these two markets has quietly shrunk, because the AI trade has stopped being a US story and become one single, global trade.
Why it matters · Korea and the Nasdaq now move together more tightly than any time since 1990, which means Korean chip stocks aren't a diversification hedge against a US tech selloff anymore, they're the same trade.
Worth asking · Is this Korea-Nasdaq lockstep just the AI trade going global, or a warning that there's nowhere left to hide if the AI trade cracks?