#SKHynixTopsKOSPIByMarketCap

SK Hynix Briefly Ousted Samsung from the Top of KOSPI But the Crown Only Lasted Overnight This data is rewritten and expanded from coverage by several media outlets (Yahoo Finance, KED Global, Nikkei Asia, Fortune) discussing the events of June 22, 2026. The following adds the continuation of the story the market crash on June 23 along with a contextual analysis rarely highlighted: why SK Hynix's victory was so fragile, and what structural risks lurk behind South Korea's AI euphoria. History Changed in a Matter of Hours On June 22, 2026, for the first time in over 25 years, Samsung Electronics was displaced from its position as the company with the largest market capitalization on KOSPI. Its displacer was SK Hynix, a memory chip maker that nearly went bankrupt two decades ago due to heavy debt. Its shares closed up 5.6% at 2,919,000 won, pushing its market cap past 2,082.5 trillion won approximately US$1.35 trillion surpassing Samsung, which sat at 2,081.3 trillion won at the time. The victory margin was thin, only about 1.2 trillion won, but enough to mark a new chapter in history. What was not widely reported in the initial media coverage was that this victory lasted less than 24 hours. The Next Day, the Market Reversed Brutally On June 23, KOSPI plunged nearly 10% the fifth largest daily decline in the index's history triggering circuit breakers twice in a single day, a rare occurrence. SK Hynix and Samsung both fell more than 12%, and their positions reversed again: Samsung rose to 2,212 trillion won, while SK Hynix fell to 1,958 trillion won. What triggered such a rapid reversal Three things happened almost simultaneously 1. MSCI again did not include South Korea on its Developed Markets watchlist, removing the catalyst for passive fund inflows that foreign investors had been awaiting. 2. Regulators began scrutinizing single-stock leverage ETFs approved just a month earlier products that amplify price movements of SK Hynix and Samsung, both up and down. 3. Foreign investors net sold 5.79 trillion won (about US$3.8 billion) of KOSPI stocks in a single session, while retail investors aggressively bought 11.11 trillion won showing a split in confidence between institutional and retail players. What made the impact so severe was not just sentiment, but concentration: Samsung and SK Hynix now account for about 48% of total KOSPI market cap, up sharply from just 34% at the end of last year. When those two stocks fall together, the entire index has virtually nowhere to hide. Why Did SK Hynix Rise So High Its Fundamentals Are Real Despite stock price volatility, the rise in SK Hynix's value is not merely a speculative bubble. Some underlying fundamental data SK Hynix's global HBM (High Bandwidth Memory) market share reaches 57 62%, making it the main supplier for Nvidia's AI accelerators. Operating margin reached 72% in the first quarter of 2026 surpassing Nvidia's margin in the same period (65%), an achievement never before seen in the semiconductor manufacturing industry. First-quarter revenue surged 198% YoY to US$52.6 billion, with operating profit up 405% YoY. Its stock has soared about 190 347% year-to-date in 2026 (depending on the measurement period), far exceeding Samsung's gain of around 193%. The main reason is structural scarcity. Goldman Sachs research estimates the global DRAM supply-demand gap widened from 3.3% to 4.9% the most severe level in 15 years. Meanwhile, new production facilities from Samsung, Micron, and even SK Hynix itself will not begin operation until at least mid-2027. Why Did Samsung Lose When Its Business Is Larger Ironically, Samsung is actually a much larger and more diversified company covering phones, home electronics, displays, and semiconductor fabrication for other clients. But amid the AI supercycle, this diversification became a burden, not an advantage. Analysts believe Samsung's broad portfolio dilutes the profits from the AI memory boom compared to SK Hynix, whose focus is almost entirely on memory chips. Additionally, expectations for SK Hynix's ADR (American Depositary Receipt) listing on the U.S. exchange in the second half of 2026 which could open access to a wider base of global investors helped drive its stock rally. Risks Rarely Discussed The Leverage ETF Time Bomb One angle missing from early coverage is the role of single-stock leverage ETFs in amplifying volatility. Three SK Hynix-based leverage ETF products landed on the Korea Exchange's watchlist after pricing practices were found to deviate sharply from net asset value in one incident, the price premium reached nearly 86% above NAV. The number of reports related to ETF price anomalies surged 32% this year compared to last year, and nearly tripled compared to 2024. This is not a technical detail to overlook these products were instrumental in magnifying price moves during the forced liquidation on June 23. So, Who Really Won The most honest answer is that there is no permanent winner. By the close of the June 23 session, Samsung had regained the top spot on KOSPI by market cap. But analysts including Han Ji-young from Kiwoom Securities and Peter Kim from KB Securities call this correction a short-term deleveraging event, not a sign of the end of the semiconductor supercycle. The risk of oversupply, they say, is still at least two years away. What deserves more attention is not who is number one today, but the structural shift underway: in less than a year, two companies now determine the fate of more than half the stock market value of a G20 country. That is a far bigger and riskier story than a one-day exchange of crown positions. What to Watch Next Micron's quarterly results (a US company, direct competitor in the HBM market) will serve as an indicator of the direction of global memory market sentiment going forward. - SK Hynix's ADR plan on the US exchange in the second half of 2026 if realized, could broaden its investor base and drive inclusion in global indices. The MSCI decision on South Korea's status in Developed Markets, which will continue to be a sentiment driver for foreign fund flows. The concentration risk of the KOSPI index itself as long as two stocks dominate nearly half the index weight, sharp volatility could recur at any time.
Sources: KED Global, Nikkei Asia, Bloomberg, TradingKey, BeInCrypto, GuruFocus, and Korea Exchange reports.