Kospi Logs Record 606-Point Gain, Retakes 7,800 as Samsung, SK Hynix Surge

Kospi Posts Biggest Gain on Record on Multiple Tailwinds

Chip Rally Lifts Index Back Above 7,800

Record 606-Point Advance

Buy Sidecars Triggered on Both Kospi and Kosdaq

Cooling Treasury Yields, Lower Oil and Samsung Labor Deal Boost Sentiment

Samsung Electronics Surges 8.5%, SK Hynix Jumps More Than 11%

South Korea’s Kospi index surged 8% on May 21, reclaiming the 7,800 level as U.S. Treasury yields eased, oil prices fell and Samsung Electronics reached a labor agreement.

The Kospi closed at 7,815.59, up 606.64 points, or 8.42%, from the previous session. That was the largest point gain on record. The previous record was 490.36 points on March 5. The benchmark also finished above 7,800 for the first time since May 14.

After opening 3.8% higher, the index extended gains early in the session, triggering buy sidecars on both the Kospi and Kosdaq markets. It was the first time buy sidecars were activated on both markets since April 8.

The rebound followed a broad rally on Wall Street as the recent run-up in U.S. Treasury yields and international oil prices eased. President Donald Trump said negotiations with Iran were in their final stage.

Technology shares also drew support after Nvidia, a leading artificial intelligence stock, reported strong earnings. The company posted record revenue for a 12th straight quarter. Adjusted earnings per share came in at $1.87, topping Wall Street expectations of $1.76.

Investor sentiment was also buoyed after Samsung Electronics and its labor union reached a last-minute wage agreement overnight, easing concerns about a strike.

Institutional investors led the rally. They were net buyers of 2.883 trillion won on the Kospi market. Foreign investors and retail investors were net sellers of 233 billion won and 2.647 trillion won, respectively.

Most of the Kospi’s biggest stocks advanced. Samsung Electronics rose 8.51% to close at 299,500 won after the wage deal eased strike concerns. The stock briefly touched 300,000 won in premarket trading. SK Hynix also jumped more than 11%, climbing back above 1.9 million won.

The sharp gains in Samsung Electronics and SK Hynix lifted related shares including SK Square, Samsung Electronics preferred shares, Samsung Life Insurance and Samsung C&T. LG Electronics hit the daily limit as expectations for its robotics business gained traction.

The Kosdaq index, which had fallen for four straight sessions, also rebounded. It closed at 1,105.97, up 4.73% from the previous day. On the Kosdaq market, foreign investors and institutions were net buyers of 137 billion won and 139 billion won, respectively. Retail investors were net sellers of 258 billion won.

On the Kosdaq, semiconductor materials, parts and equipment stocks and robotics shares were among the biggest gainers, including Wonik IPS, up 11.8%, EO Technics, up 18.61%, and Rainbow Robotics, up 16.77%. MakinaRocks, which quadrupled from its IPO price in its debut session, also closed limit-up.

The won-dollar exchange rate edged lower. In Seoul trading, the won finished the daytime session at 1,506.1 per dollar, down 0.7 won from the previous session.

Noh Jeong-dong, Hankyung.com reporter, dong2@hankyung.com