South Korean stocks surged to record highs on Monday as a significant influx of retail “ant” investors targeted chipmakers, driven by renewed optimism surrounding artificial intelligence (AI) following a rally in U.S. markets and positive data releases.
Leading the charge were heavyweights Samsung Electronics and SK Hynix, which saw their shares increase by 6.3% and 11.5%, respectively, reaching all-time peaks. This rally underscores the escalating global demand for AI hardware, which has become a dominant influence in equity markets, placing South Korea’s chip-heavy benchmark among the world’s top-performing indices.
Last week, Samsung, the leading memory chip producer globally, became only the second Asian company—after Taiwan Semiconductor Manufacturing Company (TSMC)—to surpass a trillion-dollar market capitalization, reinforcing South Korea’s pivotal role in the AI sector.
The benchmark KOSPI index closed 324.24 points higher, or up 4.32%, at 7,822.24, having previously breached a “sidecar” trading curb with a 5.35% jump to a record 7,899.32. With a remarkable 13.6% rise last week—the largest weekly increase since late 2008—the index is poised to exceed the 8,000 mark less than a week after it crossed 7,000 for the first time.
With an 86% increase this year, coupled with a 76% rally in 2025, South Korea has emerged as the best-performing major market, attributed to a 150% spike in chip exports in the initial days of May alone.
On Friday, the Philadelphia Semiconductor Index rose by 5.5%, propelled by a 15.5% surge in shares of Micron Technology, alongside gains by Apple and Intel following reports of a partnership in chip production.
In the currency market, the Korean won traded at 1,472.4 per U.S. dollar, down 0.69% from the previous close of 1,462.3.
Retail investors played a crucial role in Monday’s KOSPI rally, which outperformed Japan’s Nikkei and stocks in China and Taiwan. They net purchased 2.9 trillion won ($1.97 billion) worth of shares, while foreign investors were net sellers, offloading 3.5 trillion won in equities.
“There is profit-taking pressure rising among all investor groups, so it is necessary to note that short-term volatility can grow in semiconductor stocks as the KOSPI extends gains this week,” commented Han Ji-young, an analyst at Kiwoom Securities.
The Financial Supervisory Service (FSS) issued a warning to retail investors about the risks of chasing short-term gains, advising caution regarding a sector-led rally in a rare briefing. The FSS stated, “We are closely monitoring the trend of leveraged stock investments and risk management by securities brokerages, and will take pre-emptive measures if needed to ensure market stability.”
As of Friday, retail investors’ leveraged investments in KOSPI shares totaled 24.9 trillion won, just shy of the record 25.0 trillion won marked in late April. They have invested a total of 7.5 trillion won in KOSPI shares this month, with Samsung Electronics and SK Hynix accounting for 3.7 trillion won.
This year, Samsung Electronics and SK Hynix have both exceeded gains of 120% and 160%, respectively, compared to a 15% increase for U.S.-based Nvidia and a 44% rise for Taiwan’s TSMC. On Monday, among the 897 traded issues, 147 stocks advanced while 738 declined.
Published on May 11, 2026.
