According to Reuters, South Korea's semiconductor exports rose 260 percent year‑on‑year in 2026 so far, helping the country's total exports to nearly double this year. That surge has been driven largely by demand for memory chips and has propelled major Korean manufacturers such as Samsung and SK Hynix into the spotlight.
What the rally did to markets
Shares of Samsung and SK Hynix roughly doubled over a year, and the two companies' combined market value approaches $2,000 billion. The Kospi index rose about 77 percent year‑on‑year, a gain that also lifted other large Korean firms including LG, Hyundai and Kia.
The rapid appreciation, however, increased vulnerability. In early October the rally stalled: the Kospi lost 13 percent in a single week, and on one Thursday market selling produced an intraday drop of more than 8 percent, prompting Seoul's stock exchange to suspend trading for twenty minutes. Samsung fell 8–9 percent that day while SK Hynix slid more than 10 percent.
Causes of the correction
Several factors contributed to the sell‑off. Retail investors entered the market in force during the run‑up and increasingly used leverage. Initially they bought with their own funds, but later many took leveraged positions akin to borrowing, raising the risk of sharp losses. The Korean financial regulator had approved products such as single‑stock ETFs that offered leveraged exposure to individual names — notably Samsung — and although the regulator later limited these products, many retail investors were already exposed when prices reversed.
Investors are also reassessing whether the massive investments funnelled into artificial intelligence will deliver sustained returns, and whether the exceptional margins on memory chips can endure.
Chinese challengers and capacity expansion
Korean producers have begun significant capacity expansions, while Chinese competitors—most notably ChangXin Memory Technologies (CXMT)—are scaling up. CXMT listed on the Shanghai exchange in July 2026; after the IPO its founder, Csu Ji‑ming, was estimated to have a $15 billion fortune. Csu pledged an unusual distribution of equity, allocating half his stake — 768 million shares — among some 20,000 employees.
If Chinese manufacturers bring substantial new capacity to market, prices and profit margins could be compressed over time, as has happened in other boom sectors.
Re‑pricing and ETF outflows
Although some Korean stocks now trade at modest valuations (for a few leading names investors pay only four to five times annual earnings), markets doubt the sustainability of exceptional profitability. ETFs focused on memory manufacturers, such as the Roundhill DRAM ETF—where Micron, Samsung and SK Hynix constitute a large share of holdings—have also paused, reflecting investor caution about the sector as a whole.
Among other notable players, Japan's Kioxia (formerly Toshiba Memory) has its own proprietary technology and saw its share price rise about 400 percent over a year.
Broader financial implications
The AI investment wave is reshaping global capital markets. Large U.S. technology firms (for example Meta, Amazon, Microsoft, Google, Oracle and Apple) are spending heavily on AI development and infrastructure, competing for capital in debt and equity markets and potentially raising funding costs for others, including sovereign issuers. That financing surge introduces additional risks, and it's uncertain which investments will ultimately prove profitable.
Conclusion
South Korea emerged in 2026 as one of the notable beneficiaries of the AI boom: semiconductor exports and the stock market experienced extraordinary growth. Yet the swift market correction underlines the fragility of gains driven by elevated profit margins, retail leverage and fears of capacity‑led margin erosion as Chinese competitors scale up. Investors now face the question of how long the current profitability environment can persist and what it implies for global financial markets.
