The global memory chip industry is experiencing a transformation with few modern parallels, as relentless demand from artificial intelligence development triggers a historic repricing of the semiconductor sector. Within 24 hours, two of the world's leading memory chipmakers—South Korea's SK Hynix and US-based Micron Technology—each crossed the $1 trillion (€860bn) market capitalisation threshold for the first time.
SK Hynix shares surged as much as 13% in Seoul trading on Wednesday, reaching a new all-time high and pushing its valuation above the trillion-dollar mark. The company is now only the second South Korean firm and the third Asian company overall to join the trillion-dollar club, following rival Samsung Electronics—which crossed the same milestone earlier this month—and Taiwan's TSMC. SK Hynix shares have risen approximately 250% since the start of the year, and the stock's gain since April 2025 has exceeded 1,200%.
The milestone came a day after Micron Technology soared 19% on Wall Street, its biggest single-session gain since 2011, propelling the American chipmaker past the same valuation mark. Micron shares have jumped roughly 190% since the beginning of 2026, and the stock's gain since April 2025 has crossed 1,300%.
Both firms are dominant suppliers of high-bandwidth memory (HBM), the specialised chips at the core of AI accelerators and data centre servers. SK Hynix, a key supplier to Nvidia, has already sold out its entire 2026 HBM production capacity. The semiconductor rally has been a key driver behind one of the most remarkable stock market surges in recent years.
KOSPI Hits Record High
South Korea's KOSPI index has been a major beneficiary of the rally. The index rose as much as 2.9% on Wednesday to a new all-time high of 8,457 points. The KOSPI is up over 100% since the start of the year, after falling more than 20% during March when the Iran war broke out. From its lows in December 2024, the index has more than doubled, marking one of the fastest re-ratings of any major global benchmark in recent memory.
For European investors, the memory chip boom underscores the continent's reliance on Asian and American semiconductor supply chains. European companies such as ASML, Infineon, and STMicroelectronics have also seen gains, but the HBM market remains dominated by SK Hynix, Samsung, and Micron. The rally has also lifted sentiment in European tech indices, though the direct exposure remains limited.
SK Hynix is now eyeing a US listing. The company has filed with the US Securities and Exchange Commission to list American Depositary Receipts (ADRs) in the United States, with reports suggesting the offering could raise billions of dollars in the second half of 2026. Proceeds are earmarked for its Yongin HBM production hub in South Korea and its packaging facility in Indiana. ADRs are negotiable certificates issued by US depositary banks that represent ownership shares in foreign companies, allowing American investors to buy and trade foreign stocks on US exchanges without cross-border complexities.
While the near-term outlook remains buoyant, risks persist. Geopolitical tensions, potential export controls, and the cyclical nature of the memory chip market could temper future gains. For now, however, the AI-driven demand shows no signs of abating, and the trillion-dollar club in semiconductors is likely to welcome more members in the months ahead.
