Kospi-Nasdaq 100 60-day correlation climbs to 0.50, highest since 2021, Rayliant data show
The 60-day correlation between South Korea's Kospi and the Nasdaq 100 has climbed to approximately 0.50, its highest reading since 2021, according to data from Rayliant. At that level, the two indices are moving together more closely than at any point in roughly five years. Investors holding both U.S. and Korean equities on the premise that the two markets run independently are carrying more linked exposure than the setup may suggest.
Key takeaways
- The 60-day correlation between South Korea's Kospi and the Nasdaq 100 has climbed to approximately 0.50, its highest level since 2021, according to Rayliant data.
- A correlation of 0.50 means the two indices are in meaningful agreement on direction over the past two months, ranging on a scale from minus one to one.
- At 0.50, geographic diversification between U.S. and Korean equity holdings works less efficiently, since a drawdown in one index is more likely to coincide with a drawdown in the other.
- Because the reading uses a 60-day window, a break in the shared conditions driving both markets would push the correlation lower and restore some separation.
- The 2021 level is the reference point: holding at or above 0.50 signals a tight link, while a reversal below it would indicate decoupling is underway.
The 60-day correlation between South Korea's Kospi and the Nasdaq 100 has climbed to approximately 0.50, its highest reading since 2021, according to data from Rayliant. At that level, the two indices are moving together more closely than at any point in roughly five years. Investors holding both U.S. and Korean equities on the premise that the two markets run independently are carrying more linked exposure than the setup may suggest.
What Rayliant's data show
Correlation runs from minus one to one. Zero means two assets move without relationship. One means they move in perfect sync. At 0.50, the Kospi and the Nasdaq 100 are in meaningful agreement on direction over the past two months. The current reading is the highest Rayliant has recorded for this pair since 2021.
That year saw both markets respond to the same broad conditions. The return to a similar reading suggests those conditions, or something comparable, are pulling U.S. and Korean equity markets back into alignment.
What a 0.50 reading means for cross-market exposure
Portfolio construction is where the number matters. Investors who hold positions in both the Kospi and the Nasdaq 100 often do so to spread geographic risk across markets that do not always move together. At a 60-day correlation of 0.50, that spread is working less efficiently than it would at a lower reading.
When two indices are moving in step at that magnitude, a drawdown in one is more likely to coincide with a drawdown in the other. The geographic buffer is present but thinner than it was.
The 60-day window means the reading is not fixed. Any break in the conditions driving both markets in the same direction would push the correlation lower and restore some separation between the two.
What to watch
The 2021 level is the reference point. If the 60-day correlation holds above 0.50 or pushes higher, the link between U.S. and Korean equities is as tight as or tighter than the prior peak. A reversal below that level would indicate decoupling is underway.
Each session, the oldest day drops off the 60-day window and the newest joins it. A sustained divergence in daily moves between the two indices would pull the reading lower. A sustained convergence would push it higher. The 60-day print from Rayliant is the number on tape.
Related reading
Filed by the macro desk of MarketPR on July 28, 2026. Source: cnbc.com. Indicative figures are not investment advice.