In a historic shift for South Korea's equity markets, SK Hynix Inc. closed Monday with a higher market capitalization than Samsung Electronics Co., marking the first time since 2000 that the memory chipmaker has claimed the top spot. The milestone underscores the market's growing bet on artificial intelligence as the primary driver of value in the semiconductor industry.
Shares of SK Hynix surged 5.6%, pushing its common-share market value to approximately 2,080.4 trillion won ($1.35 trillion). Samsung Electronics, by contrast, edged down 0.14% to 2,066.7 trillion won (excluding preferred shares). The narrow margin reflects a decisive revaluation of AI-focused memory suppliers over diversified conglomerates.
AI Memory Boom Fuels Revaluation
The rally is rooted in the explosive demand for high-bandwidth memory (HBM), a specialized chip crucial for Nvidia Corp.'s AI accelerators. SK Hynix has emerged as the dominant supplier, capturing 61% of the global HBM market by 2025, compared with Samsung's 17% and Micron Technology's 21%, according to industry data. This leadership has allowed SK Hynix to command premium pricing, unlike the commoditized DRAM market.
SK Hynix shares have skyrocketed more than 340% this year, reflecting investor confidence that the AI memory cycle is not merely a cyclical upswing but a structural transformation. "The emergence of customized AI memory has fundamentally changed the economics of the sector," said Kim Sunwoo, senior analyst at Meritz Securities, in an interview with Reuters.
Index Constraints and Market Mechanics
Part of the shift is mechanical. Exchange-traded funds tracking the MSCI Korea Index face concentration limits under the MSCI 25/50 rule, which caps any single issuer at 25% and aggregate holdings above 5% at 50%. As of May 29, Samsung represented 33.73% of the MSCI Korea Index and SK Hynix 28.62%. With both stocks swelling, ETFs such as BlackRock's iShares MSCI South Korea ETF ($26.3 billion in assets) are approaching their capacity to hold more, potentially amplifying demand for the smaller of the two.
SK Hynix's U.S. Listing Ambitions
SK Hynix is also targeting a Nasdaq listing of American depositary receipts as soon as August, according to Reuters. The move would broaden its investor base, particularly among U.S.-based chip and AI funds. The company's journey from near-collapse in 2002—when it was run by creditors under the name Hynix Semiconductor—to the cusp of a U.S. listing underscores a remarkable turnaround. SK Group Chairman Chey Tae-won had previously urged the company to create "indispensable products" rather than generic memory chips.
Samsung's Pushback and Broader Implications
Samsung has contested the valuation comparison, arguing that preferred shares should be included in its market cap. By that measure, Samsung's total value stood at 2,246.4 trillion won as of Monday's close. However, Bank of America data cited by Reuters indicates that while Samsung still leads in monthly DRAM wafer output, SK Hynix could significantly narrow the gap by 2028.
The dominance of AI-memory stocks has caught the attention of regulators. South Korea's Financial Supervisory Service chief Lee Chan-jin stated Monday that approvals for leveraged ETFs tied to Samsung and SK Hynix were "prepared hastily" and that the agency is "seriously looking into" steps to stabilize the market after retail borrowing hit a record 60 trillion won by end of May.
Market Outlook
Investors now face a critical question: Is SK Hynix's ascent a lasting revaluation of AI leaders, or a crowded trade amplified by index mechanics? For now, the market is betting that the company closest to the HBM supply squeeze deserves a premium. Samsung, once the unquestioned bellwether of Korean technology, no longer trades as the default proxy for the sector.
