KOSPI's AI Semiconductor Value Chain Takes Over, Sweeping Market Cap Ranks 1 to 5

Artificial intelligence (AI) semiconductors are reshaping the landscape at the top of the Korea Composite Stock Price Index (KOSPI). While Samsung Electronics and SK hynix have held on to the No. 1 and No. 2 spots in market capitalization, SK Square and Samsung Electronics Co., Ltd. Preferred Shares have climbed to No. 3 and No. 4, respectively. Samsung Electro-Mechanics has also overtaken Hyundai Motor Company to enter the top five. Overall, the market's semiconductor-heavy rally has moved beyond lifting the index and is now changing the ranking of large-cap stocks.
According to the Korea Exchange (KRX) on the 31st, the top five KOSPI companies by market capitalization as of the 29th were Samsung Electronics, SK hynix, SK Square, Samsung Electronics Co., Ltd. Preferred Shares, and Samsung Electro-Mechanics. Samsung Electro-Mechanics ranked fifth after its market cap reached 158.8735 trillion won, surpassing Hyundai Motor Company's 148.0398 trillion won. The gap between the two companies widened to 10.8336 trillion won.
The change in Samsung Electro-Mechanics' ranking is even more striking when compared with the start of the year. At the end of January, it ranked 36th in market capitalization. It then rose to 26th at the end of February, 22nd at the end of March, and 11th at the end of April, before jumping to fifth place at the end of May. Hyundai Motor Company has also drawn attention on expectations for physical AI, but Samsung Electro-Mechanics has expanded its market cap more quickly as demand rose for multilayer ceramic capacitors (MLCC) that stabilize power supply and for package substrates used in high-performance semiconductors. That shift has altered the upper tier of the market.
Oh Kang-ho, a researcher at Shinhan Securities, said, "Since the AI market began to open up, Samsung Electro-Mechanics' MLCC and substrate businesses have entered a structural growth cycle." He added, "As investment in AI servers and data centers expands demand for high-value-added components, expectations for higher supply prices are also rising, making it possible for both earnings and valuations to move up together."
Changes in market-cap rankings are also visible within the AI semiconductor value chain. As of the 29th, Samsung Electronics had a market cap of 1,853.2703 trillion won, while SK hynix stood at 1,662.7346 trillion won. SK hynix's market cap had risen to 89.7% of Samsung Electronics'. At the end of January, that ratio was 69.7%, but by the end of May it had climbed to nearly 90%. With SK hynix benefiting more strongly from its leadership in the high bandwidth memory (HBM) market and expectations for an AI semiconductor supercycle, the gap between the No. 1 and No. 2 stocks is narrowing quickly. The market share of the AI semiconductor value chain is also rising fast. The combined share of Samsung Electronics, SK hynix, SK Square, Samsung Electronics Co., Ltd. Preferred Shares, and Samsung Electro-Mechanics in total KOSPI market capitalization expanded from 41.8% at the end of January to 57.7% at the end of May. In other words, more than half of KOSPI's market cap is now concentrated in AI semiconductor-related large caps.
In fact, among the 2,874 stocks traded in the domestic market in May, only 368, or 12.8%, rose, while 2,385, or 83.0%, fell. Despite the index's gains, the market's momentum was not spreading broadly. Instead, it was concentrated in a handful of AI semiconductor names.
Securities analysts expect the AI-driven concentration to continue. They say shortages in memory supply caused by expanded HBM production, combined with Big Tech's growing AI investments, are spreading the premium that began with semiconductor chips to the broader AI hardware value chain, including substrates and components.
koreanbae@fnnews.com Bae Han-geul Reporter