South Korea's KOSPI stock index rose 87.68% from Jan 2 to reach 8088.34, but the rally was driven by effectively just six stocks, according to market concentration analysis released this week. The Herfindahl-Hirschman Index (HHI) for KOSPI hit a record high, translating to an effective stock count of 5.75, meaning six stocks now control the index's direction despite over 900 listed companies. Samsung Electronics and SK Hynix concentrated investor capital and earnings growth, with semiconductors accounting for 79% of KOSPI's market capitalization increase during the period, while the KOSDAQ index posted negative returns. The concentration intensified after single-stock leveraged ETFs launched on May 27, channeling retail funds into the two semiconductor giants. Analysts attribute the polarization to earnings concentration in semiconductors, IT hardware, and banks, creating a structural gap between large-cap and small-cap stocks.
KOSPI HHI Reaches Record High with Effective Stock Count at 5.75
According to the Korea Exchange, KOSPI closed at 8088.34, up 5.76% from the previous trading day. This represents an 87.68% gain from the Jan 2 closing price of 4309.63. Financial data provider FnGuide reported that KOSPI's HHI reached an all-time high as of the previous trading day. When converted to an effective stock count (1/HHI), the figure stood at 5.75, indicating that approximately six stocks effectively determine the entire KOSPI index direction when weighted by market capitalization. The concentration phenomenon deepened after the May 27 launch of single-stock leveraged ETFs, which funneled retail investor funds into Samsung Electronics and SK Hynix, while foreign investors maintained semiconductor-focused trading patterns.
Semiconductors Account for 79% of KOSPI Market Cap Increase
Capital flows during the first half concentrated heavily in semiconductors. Shinhan Investment Securities analyzed that while KOSPI rose over 100% in the first half, 79% of the market capitalization increase originated from the semiconductor sector. The firm stated that distinguishing between semiconductors and non-semiconductors became more meaningful than separating KOSPI and KOSDAQ, reflecting the clarity of the semiconductor-centered market trend. Large-cap concentration was confirmed in corporate earnings data. Yuanta Securities reported that KOSPI-listed companies' 12-month forward net profit consensus increased by 11.8 trillion won week-over-week, while KOSDAQ's consensus decreased. Kang Jin-hyuk, senior researcher at Shinhan Investment Securities, stated: "The first-half market repeated large-cap concentration and sector rotation, but ultimately semiconductor-centered flows dominated the market." Lee Jae-won, researcher at Yuanta Securities, stated: "The fundamental reason stock prices concentrate in specific stocks is ultimately because profits concentrate in one direction. A strategy centered on KOSPI large-caps where earnings and fund flows are simultaneously confirmed—such as semiconductors, IT hardware, and banks—remains valid."
Analysts Forecast Continued Semiconductor-Led Rally in Second Half
Securities firms assign high probability to the continuation of semiconductor-centered strength in the near term. Samsung Futures projected that semiconductor-centered strength will continue in the second half based on expanded AI infrastructure investment and earnings improvement. The firm diagnosed that caution is necessary if aggressive capital inflows intensify market overheating and stock concentration. Market experts view the likelihood as high that relative neglect of non-leading KOSPI stocks and KOSDAQ will deepen in tandem with the continuation of semiconductor-led gains. A securities industry official stated: "In the first half, KOSPI rose over 100% while KOSDAQ recorded negative returns, confirming polarization. If semiconductor-centered concentration continues in the second half, a market condition may persist where the index hits new highs but investors' perceived returns remain low." Kang Jin-hyuk added: "There is a possibility that the large-cap-centered market will continue in the second half as semiconductor relay momentum persists."
FAQ
What caused KOSPI stocks to concentrate in just six stocks?
The concentration resulted from investor capital and earnings growth focusing on Samsung Electronics and SK Hynix. The launch of single-stock leveraged ETFs on May 27 accelerated retail fund inflows into these two semiconductor giants, while foreign investors maintained semiconductor-focused trading. The Herfindahl-Hirschman Index reached a record high, with an effective stock count of 5.75, meaning six stocks effectively control KOSPI's direction despite over 900 listed companies.
How much of KOSPI's market cap increase came from semiconductors?
Shinhan Investment Securities analyzed that 79% of KOSPI's market capitalization increase during the first half originated from the semiconductor sector. KOSPI-listed companies' 12-month forward net profit consensus increased by 11.8 trillion won week-over-week, while KOSDAQ's consensus decreased, confirming earnings concentration in large-cap semiconductors, IT hardware, and banks.
Why did KOSDAQ post negative returns while KOSPI rose 87%?
The polarization occurred because capital flows and earnings growth concentrated in KOSPI large-cap semiconductors rather than KOSDAQ stocks. A securities industry official stated that KOSPI rose over 100% in the first half while KOSDAQ recorded negative returns, confirming market polarization. Analysts attribute this to profits concentrating in specific sectors, making the distinction between semiconductors and non-semiconductors more meaningful than separating KOSPI and KOSDAQ.
