South Korean Shares Rally on US-Iran Ceasefire

The benchmark KOSPI fell 2.70% to close at 6,890 on Monday, reversing gains from the previous session amid renewed uncertainty over the Middle East and higher oil prices. Brent crude rose above $105 a barrel after the US rejected Iran’s conditional proposal concerning the Strait of Hormuz. Additionally, the 10-year US Treasury yield remained near its highest level since July 2007, raising concerns over tighter global financial conditions and further rate hikes. Investors took profits in large-cap technology stocks, with Samsung Electronics and SK hynix declining 4.73% and 4.56%, respectively, along with losses in SK Square (-7.56%), Samsung C&T (-5.72%), SK Inc (-4.91%), and Hyosung Heavy Industries (-4.01%). Meanwhile, strong semiconductor earnings prospects provided some offset, with Samsung Electronics expected to post more than KRW 100 trillion in third-quarter operating profit and the semiconductor sector’s business sentiment reaching a record high for the fourth quarter.

The benchmark KOSPI rose 0.90% to close at 7,081 on Wednesday, extending gains for a fourth consecutive session as record-high Nasdaq and advances in AI-related stocks boosted Korean chipmakers. Samsung Electronics and SK hynix rose 2.89% and 0.98%, respectively, while SK Square (3.97%), Samsung Electro-Mechanics (1.28%), SK Inc (4.25%), and SK Innovation (6.03%) also gained. Additionally, easing Middle East tensions lifted the broader market as US and Iranian officials held a three-hour meeting, raising hopes for diplomatic progress, while oil prices fell around 1%. At the same time, South Korean President Lee Jae Myung and US President Donald Trump welcomed progress on strategic investment projects under their $350 billion package, including potential projects in Texas gas-fired power, nuclear energy and Alaska LNG, as well as cooperation in shipbuilding and nuclear-powered submarines. The market will remain closed for the Chuseok holiday and resume trading on September 28.

The benchmark KOSPI rose 0.15% to close at 7,018 on Tuesday, extending its winning streak to a third consecutive session as a rally in AI-related US stocks lifted Korean chipmakers. The Nasdaq Composite jumped 2.3% to a record high, while the US semiconductor sector climbed strongly, reinforcing confidence in AI demand. Samsung Electronics rose 1.28%, while other notable performers included Samsung Electro-Mechanics (3.78%), Doosan Enerbility (1.29%), HD Hyundai Heavy Industries (1.11%), LG Electronics (6.42%), LS Electric Co (1.20%), and SK Inc (2.09%). Additionally, lower oil prices and US Treasury yields eased concerns over imported inflation and borrowing costs, contributing to the broader upturn. Meanwhile, investors remained focused on the upcoming US-China summit, where AI, tariffs and rare earths are expected to be discussed, with the outcome potentially affecting trade and technology supply chains.