South Korea's stock market rebounded nearly 3% on Thursday, shaking off the previous session's shock, as foreign and institutional investors returned with aggressive buying amid easing geopolitical risk concerns stemming from the Middle East. Leading stocks across semiconductors, shipbuilding, defense, and nuclear energy rose in unison. However, individuals sold off more than 2 trillion won, reflecting fatigue from the recurring "Black Monday" pattern that has persisted since March amid concerns that full-scale U.S. military operations could unfold over the weekend.
The Korea Composite Stock Price Index (KOSPI) closed at 5,377.30 on Thursday, up 143.25 points (2.74%) from the previous session. Foreign investors, who turned to net buying for the first time in 12 trading days since March 18, led the supply-demand dynamics on the main bourse. Foreigners, who started the day as net sellers, steadily expanded their purchases through the closing bell, scooping up 814.5 billion won worth of shares. Institutions added 716.9 billion won in net purchases.
Individual investors, meanwhile, dumped 2.0879 trillion won worth of shares as anxiety from the previous day's plunge collided with the desire to lock in short-term gains. The impact of U.S. President Donald Trump's remarks about "attacking Iran within two to three weeks" had not dissipated. Analysts noted that retail money fled as the pattern of weekend surprises followed by Monday sell-offs had repeated every week for more than a month since the onset of hostilities. U.S. markets were also closed Friday for Good Friday.
Despite the retail selling, the combined foreign and institutional buying wave lifted most large-cap stocks by market capitalization into positive territory. Samsung Electronics (005930.KS) surged 4.37%, and SK hynix (000660.KS) jumped 5.54%, recovering the previous day's losses. Samsung Electronics preferred shares gained 4.89%, Doosan Enerbility rose 3.21%, SK Square added 2.88%, Hanwha Aerospace (012450.KS) climbed 2.26%, and Hyundai Motor (005380.KS) advanced 1.18%.
Sectors with structural demand outlooks also rallied amid the geopolitical uncertainty. Shipbuilding stocks including HD Hyundai Heavy Industries surged 9.23% and Hanwha Ocean (042660.KS) jumped 7.29%. Defense stock LIG Nex1 soared 9.69%. LG Energy Solution (373220.KS) fell 1.48%, Samsung Biologics (207940.KS) dropped 1.96%, and Kia (000270.KS) slipped 0.27%, unable to overcome intraday weakness.
The KOSDAQ index closed at 1,063.74, up 7.40 points (0.70%) from the previous session, showing more muted upside momentum compared with the KOSPI. The supply-demand picture was the exact opposite of the main bourse. Individuals single-handedly defended the index with 406.2 billion won in net purchases, while foreigners and institutions net sold 197.1 billion won and 217.8 billion won, respectively.
Among the top KOSDAQ stocks by market capitalization, Alteogen rose 3.84%, reclaiming the No. 1 spot by market cap, overtaking the underperforming EcoPro (-0.63%) and EcoPro BM (-2.18%). Samchundang Pharmaceutical, which had shown extreme volatility recently, surged 6.40% as bargain hunters piled in on the perception of an oversold bounce, delivering another roller-coaster session. Rainbow Robotics edged down 0.55%, closing slightly lower.
On the Street, optimism that the Middle East situation has peaked — with multinational discussions on reopening the Strait of Hormuz and the imposition of a "transit tax" being floated — is mixing with concerns that troop deployments are underway and weekend military clashes could escalate, given that "April 6," the negotiation deadline mentioned by Trump, is just around the corner. "The perception that the Iran situation has peaked formed, allowing the market to confirm a floor and rebound, but the rally was capped by weekend caution, Trump-related uncertainty, and wariness ahead of tonight's employment data release," said Lee Kyung-min, a researcher at Daishin Securities.
