South Korea's KOSPI market saw a major reshuffling of its top 10 stocks by market capitalization during the first half of the year. An AI-fueled surge in semiconductor investments drove the shift. As of the July 6 closing, three new companies entered the top 10 rankings while defense and nuclear energy stocks that dominated the previous year dropped out entirely. The shift reflects concentrated capital flows into semiconductor and AI value chain stocks, with Samsung Electronics and SK Hynix now accounting for over half of the KOSPI's total market capitalization. Samsung Electro-Mechanics jumped from 32nd place at the start of the year to 4th, while SK Square rose from 7th to 3rd, according to data from the Korea Exchange. The reshuffling marks a stark reversal from the prior year's market leadership, when defense contractor and energy stocks held dominant positions in the rankings.
Three New Entrants Reshape KOSPI Top 10 Rankings
As of the July 6 closing, the KOSPI top 10 stocks by market capitalization (excluding preferred shares) were Samsung Electronics, SK Hynix, SK Square, Samsung Electro-Mechanics, Hyundai Motor, LG Energy Solution, Samsung Life Insurance, Samsung C&T, Samsung Biologics, and Kia, in that order. Compared to the first trading day of the year (January 2), Samsung Electro-Mechanics, Samsung Life Insurance, and Samsung C&T newly entered the top 10. HD Hyundai Heavy Industries, Hanwha Aerospace, and Doosan Enerbility exited the rankings. While 7 of the top 10 stocks retained their positions, individual rankings shifted significantly. The concentration of capital into semiconductor leaders Samsung Electronics and SK Hynix intensified, pulling affiliated companies like SK Square and Samsung Electro-Mechanics higher.
Samsung Electronics and SK Hynix Expand Market Cap Dominance
Samsung Electronics' weight in the KOSPI market capitalization expanded from 21.37% at the start of the year to 28.07% as of July 6. SK Hynix's share rose from 13.85% to 25.56% over the same period. The two semiconductor giants now represent over half of the exchange's total market value. The expansion reflects sustained investor inflows driven by optimism around AI chip demand and high-bandwidth memory (HBM) growth. SK Hynix's role as a key supplier to global AI semiconductor markets amplified its valuation gains, with spillover effects benefiting its holding company SK Square.
SK Square Surges to 3rd Place on SK Hynix Valuation Gains
SK Square climbed from 7th place at the start of the year to 3rd as of July 6. The holding company's stock price reached 1.495 million won on July 6, up approximately 281% from the first trading day's closing price. The surge was driven by the revaluation of SK Square's stake in SK Hynix, its core subsidiary. SK Hynix's emergence as a central player in the global AI semiconductor market—powered by its HBM product line—boosted the holding company's valuation. Samsung Electro-Mechanics also posted dramatic gains, rising from 32nd place at the start of the year to 4th as of July 6. Its market capitalization expanded from 20.1672 trillion won to 137.1376 trillion won. Samsung Electro-Mechanics recorded a year-to-date gain in the 700% range during the first half, marking the highest percentage increase among KOSPI stocks.
Samsung Group Affiliates Advance on Revaluation Expectations
Samsung Life Insurance and Samsung C&T, which ranked outside the top 10 at the start of the year, entered the rankings at 7th and 8th place respectively as of July 6. The two Samsung Group affiliates attracted investor interest amid expectations of revaluation tied to Samsung Electronics' shareholding value. The gains reflect broader momentum across Samsung Group stocks as semiconductor-driven optimism extended to affiliated companies.
Defense and Energy Stocks Exit Top 10 Amid Capital Rotation
Defense and nuclear energy stocks that led the market in the previous year fell out of the top 10 rankings. HD Hyundai Heavy Industries, Hanwha Aerospace, and Doosan Enerbility—representative stocks of the defense, aerospace, and nuclear energy sectors—all dropped below 10th place. These companies had entered the top rankings on strong price gains in the previous year, but faced profit-taking and capital rotation to semiconductor stocks during the first half. LG Energy Solution and Samsung Biologics also declined in rankings. LG Energy Solution fell from 3rd place at the start of the year to 6th, while Samsung Biologics dropped from 4th to 9th. Weakened investor sentiment in secondary battery and biotech sectors contributed to the declines.
Analysts Expect Continued Semiconductor Concentration
Lee Jae-won, a researcher at Yuanta Securities, stated that the market capitalization reshuffling directly reflects the direction of capital inflows. Lee said, "Earnings estimates for semiconductor stocks continued to be revised upward, attracting market attention, and as a result, the top market cap rankings were reorganized around those stocks. In contrast, sectors such as secondary batteries and biotech were shunned by the market." Lee noted that concentration in semiconductor stocks is likely to persist in the second half. He explained, "Currently, Samsung Electronics and SK Hynix account for more than half of the KOSPI market capitalization, and earnings are also improving centered on these two stocks. If this structure continues, the concentration in a few stocks is highly likely to persist."
FAQ
What caused the reshuffling of KOSPI's top 10 stocks during the first half of the year?
The reshuffling was driven by concentrated capital inflows into semiconductor and AI value chain stocks. Samsung Electronics and SK Hynix expanded their combined market cap weight from 35.22% to over 53%, pulling affiliated companies like SK Square and Samsung Electro-Mechanics into higher rankings. Defense and energy stocks that dominated the previous year exited the top 10 due to profit-taking and capital rotation.
How much did SK Square's stock price increase during the first half?
SK Square's stock price reached 1.495 million won as of July 6, up approximately 281% from the closing price on the first trading day of the year (January 2). The surge was attributed to the revaluation of SK Square's stake in SK Hynix, which emerged as a key player in the global AI semiconductor market through its HBM product line.
Which stocks dropped out of the KOSPI top 10 rankings?
HD Hyundai Heavy Industries, Hanwha Aerospace, and Doosan Enerbility—representative stocks of defense, aerospace, and nuclear energy sectors—dropped out of the top 10 rankings as of July 6. These companies had entered the rankings on strong gains in the previous year but faced profit-taking and reduced investor interest as capital rotated to semiconductor stocks.
