Korea’s KOSPI fell 18.8% in the third quarter—its worst quarterly drop since the first quarter of 2020, and also the worst among the major global stock indexes over the same period. During that time, the S&P 500 still rose 2.3%.
The contrast comes from this: in the first nine months of this year, the KOSPI has still gained about 60%, ranking among the world’s strongest alongside the Taiwan market. So this isn’t a case of “logic breaking down”; it’s a “dramatic correction after running up too much.”
Why did it get so bad? Three lines tightened at the same time:
First, a backlash from the concentration of AI trading. Samsung Electronics and SK Hynix together account for about half of the KOSPI’s weighting. Starting in early July, storage-chip stocks were sold off in a concentrated manner. Even though the forward P/E ratios of these two companies have already fallen to historical lows of 4–5x, when sentiment cools, the index still gets dragged along.
Second, deleveraging magnified the decline. A hedge fund with highly leveraged positions in Korean storage-chip stocks collapsed, and combined with large amounts of leveraged ETFs held by retail investors in Korea, margin calls triggered forced liquidations—turning a stampede into a cascade.
Third, external conditions tightened. Global bond yields rose; U.S. Treasury yields climbed. The Korean won came under pressure, and foreign investors steadily reduced their holdings throughout the quarter. Meanwhile, the Bank of Korea moved from cooling hot conditions to tightening policy, further suppressing valuation returns.
For ordinary users, there’s a lesson here that’s more worth taking away than “whether to catch the bottom”: when half of an index’s weight is piled onto the same theme (storage / AI), the index isn’t diversified—it’s effectively a leveraged sector ETF. The volatility of the KOSPI, at its core, is concentration risk.
My view: this round is a clearing of leverage plus a backlash from concentration, not an AI demand peak. But the 4–5x P/E ratio suggests the market is pricing in “a peak in the cycle” rather than “growth slowing.” That expectation gap is the key. The practical approach is to watch storage contract prices and whether foreign money returns—not to focus on the index’s points.
Over to you: would you treat this plunge as a buying opportunity in Korean stocks, or is it a textbook case of “concentration risk”? #KoreaKOSPIWorstQuarterSince2020
The contrast comes from this: in the first nine months of this year, the KOSPI has still gained about 60%, ranking among the world’s strongest alongside the Taiwan market. So this isn’t a case of “logic breaking down”; it’s a “dramatic correction after running up too much.”
Why did it get so bad? Three lines tightened at the same time:
First, a backlash from the concentration of AI trading. Samsung Electronics and SK Hynix together account for about half of the KOSPI’s weighting. Starting in early July, storage-chip stocks were sold off in a concentrated manner. Even though the forward P/E ratios of these two companies have already fallen to historical lows of 4–5x, when sentiment cools, the index still gets dragged along.
Second, deleveraging magnified the decline. A hedge fund with highly leveraged positions in Korean storage-chip stocks collapsed, and combined with large amounts of leveraged ETFs held by retail investors in Korea, margin calls triggered forced liquidations—turning a stampede into a cascade.
Third, external conditions tightened. Global bond yields rose; U.S. Treasury yields climbed. The Korean won came under pressure, and foreign investors steadily reduced their holdings throughout the quarter. Meanwhile, the Bank of Korea moved from cooling hot conditions to tightening policy, further suppressing valuation returns.
For ordinary users, there’s a lesson here that’s more worth taking away than “whether to catch the bottom”: when half of an index’s weight is piled onto the same theme (storage / AI), the index isn’t diversified—it’s effectively a leveraged sector ETF. The volatility of the KOSPI, at its core, is concentration risk.
My view: this round is a clearing of leverage plus a backlash from concentration, not an AI demand peak. But the 4–5x P/E ratio suggests the market is pricing in “a peak in the cycle” rather than “growth slowing.” That expectation gap is the key. The practical approach is to watch storage contract prices and whether foreign money returns—not to focus on the index’s points.
Over to you: would you treat this plunge as a buying opportunity in Korean stocks, or is it a textbook case of “concentration risk”? #KoreaKOSPIWorstQuarterSince2020