South Korea’s KOSPI closed at a record 9,063.84 on June 18, crossing 9,000 for the first time in history. The index gained 2.25% on the day. Just two stocks were responsible for most of it.
Samsung Electronics and SK Hynix together account for more than 50% of the index by market value. Both hit all-time highs, and almost everything else fell.
The Catalyst Behind the Move
SK Hynix jumped again after confirming it had shipped samples of its seventh-generation high-bandwidth memory chip, HBM4E, to major AI customers. The announcement cemented its position as the leading supplier of the specialized DRAM that powers Nvidia GPU packages and large-scale AI workloads.
Samsung Electronics also spiked. Samsung Life Insurance and SK Square, both valued largely on their stakes in the two chipmakers, posted similar gains for the same reason. Outside that cluster, the session told a different story.
Of the 917 stocks traded on the Korea Exchange, 791 declined. Hyundai Motor fell 2.75%, Kia Corp dropped 4.51%, and battery maker LG Energy Solution lost 3.85%. The headline number masked a market where most participants lost ground.
Foreign Money Piled In
Foreign investors were net buyers of approximately 1.3 trillion won ($851 million) on the day. That buying pressure was a key force lifting the index, as foreign capital flowed into the names with the clearest AI earnings story.
Daishin Securities raised its 2026 KOSPI target from 8,800 to 11,500 following the close, with analyst Lee Kyung-min writing that the index’s upside should hold as long as forward earnings estimates for chipmakers continue rising. The firm called it a classic performance and policy market.
South Korea’s financial regulator issued a separate investor warning on single-stock leveraged products tied to Samsung and SK Hynix, a signal that retail leverage in Korean equities has grown sharply alongside the index. The KOSPI crossed 9,000 in 16 trading days after first clearing 8,000. How broadly the next thousand points are shared may matter more than when they arrive.