The Kospi closed at an all-time high of 9,063.84 on June 18, 2026, gaining 2.25% in a single session. Across the East China Sea, the Nikkei 225 pushed above 66,000 points in intraday trading, also touching unprecedented territory.
The Kospi has posted gains of more than 100% year-to-date through late May. Samsung Electronics climbed 4.62% on June 18 alone, while SK Hynix surged 6.51%. Together, these two companies now account for more than 50% of the Kospi’s total market value.
SK Hynix hit a $1 trillion market capitalization in late May, becoming only the third Asian company ever to reach that level. The other two: Samsung and TSMC. The driving force behind SK Hynix’s ascent is high-bandwidth memory, or HBM — the specialized memory chips that AI servers require in enormous quantities to train and run large language models.
Japan’s rally has been lifted by semiconductor equipment firms like Tokyo Electron, which supplies the machines that fabricate chips. As chipmakers around the world expand capacity to meet AI demand, they need fabrication tools, and Japanese firms dominate several niches in this supply chain.
Exports tell the real story
