For a decade, the growth of South Korea’s capital markets followed a steady, if uninspired, trajectory. It took ten years for the number of companies with a market capitalization exceeding 1 trillion won to grow from 200 to 300. Yet, in a startling acceleration that began in late 2024, the market added its next 100 trillion-won companies in just nine months, reflecting a fundamental shift in how global investors price Korean assets. This rapid expansion is the result of a rare alignment between technological dominance and long-awaited corporate governance reform.
At the heart of this surge lies High Bandwidth Memory (HBM), the critical component that feeds data to Nvidia’s AI processors. Samsung Electronics and SK Hynix currently control approximately 80% of the global HBM market, effectively positioning South Korea as the indispensable 'bottleneck' of the global AI infrastructure. As the demand for AI data centers grows exponentially, the traditional narrative of memory as a cyclical commodity has been replaced by a premium valuation of memory as the essential fuel for large language models.
The financial results are staggering. By the first quarter of 2026, SK Hynix achieved a net profit margin of 77%, an unprecedented figure for a hardware manufacturer that actually exceeds the gross margins of some leading software firms. This influx of 'AI gold' has provided the capital necessary for these firms to engage in aggressive expansion and shareholder returns, sparking a rally that saw the KOSPI index nearly triple in value over a two-year period.
Crucially, this boom is not limited to the traditional chaebols. The junior KOSDAQ board has seen its own renaissance, with 137 companies now boasting trillion-won valuations. This diversification suggests that the concentration of power within a few family-run conglomerates is finally beginning to yield to a more decentralized ecosystem of biotech and AI application startups. This structural shift indicates that South Korea is beginning to cultivate growth outside of its traditional industrial giants.
Simultaneously, the perennial 'Korea Discount'—the systemic undervaluation of Korean firms due to poor governance—is being dismantled. Following the 2025 passage of the Commercial Act amendment and the mandatory cancellation of treasury stocks in 2026, the legislative environment has pivoted toward protecting minority shareholders. Inspired by Japan’s corporate reforms a decade ago, these measures have created a 'flywheel effect' where AI-driven profits are channeled into dividends and buybacks, attracting a new wave of global capital.
Despite this momentum, structural risks remain. South Korea’s dominance is currently concentrated in the 'hardware and infrastructure' layer of the AI stack, while it lags behind in foundational models and software applications. While the nation is reaping the rewards of 'selling sand' to the AI industry, its long-term stability will depend on whether it can move up the value chain. If HBM becomes commoditized or if architectural shifts reduce its importance, the current valuation boom could face a severe correction.