Kospi Jumps 5.5%, Triggers Buy Sidecars as Samsung Labor Deal, Nvidia Results Lift Sentiment

Source

Korea Economic Daily

Summary

The Kospi surged more than 5%% in early trading on the back of falling oil prices, easing Treasury yields and the removal of strike concerns at Samsung Electronics.
Nvidia’s 12th straight quarterly revenue record and a last-minute wage deal between Samsung Electronics and its labor union boosted sentiment toward technology shares.
Heavyweight stocks including Samsung Electronics and SK Hynix, along with the Kosdaq index, posted sharp gains, while MachinaRocks hit the daily limit, underscoring a strong rebound across both markets.

Forecast Trend Report by Period

Kospi jumps more than 5% in early trading, retakes 7,600

Buy sidecar triggered

Oil falls and bond yields ease as Iran talks progress

Samsung Electronics labor deal boosts sentiment

Kosdaq also triggers buy sidecar

*Employees celebrate in the dealing room at Hana Bank headquarters in Jung-gu, Seoul, after the Kospi topped 7,000 on May 6, 2026. Photo: Kim Beom-jun*

South Korea’s Kospi jumped more than 5% in early trading on May 21 as lower oil prices and easing Treasury yields lifted sentiment, while a wage agreement at Samsung Electronics Co. eased concerns over a strike. The sharp rebound triggered buy sidecars, or temporary curbs on program buy orders, on both the Kospi and Kosdaq markets.

As of 9:37 a.m., the Kospi had risen 398.27 points, or 5.52%, to 7,607.22. The benchmark opened up more than 3% and extended its gains.

The surge also set off a buy sidecar on the Kospi. The market-stabilization measure halts the effectiveness of program trading orders for five minutes. On the Kospi, it is triggered when Kospi 200 futures rise or fall more than 5% from the previous session’s close and stay there for at least one minute.

The rebound followed a broad rally on Wall Street after the recent spike in US Treasury yields and global oil prices eased. President Donald Trump said negotiations with Iran were in their final stage.

Nvidia Corp., a bellwether for the global artificial intelligence trade, also supported technology shares after reporting better-than-expected results. The company posted a 12th straight quarterly revenue record. Adjusted earnings per share came in at $1.87, beating Wall Street estimates of $1.76.

Sentiment also strengthened after Samsung Electronics and its labor union reached a last-minute agreement in wage talks the previous night, easing fears of a strike.

At that time, retail and institutional investors were net buyers of 636.9 billion won and 312.1 billion won, respectively, on the Kospi. Foreign investors were net sellers of 996.3 billion won.

Among individual stocks, Samsung Electronics and SK Hynix Inc. rebounded. Samsung Electronics was up 6.7% at 294,500 won, while SK Hynix gained 5.33% to 1.838 million won.

Samsung Electro-Mechanics Co. rose 12.06%, Hyundai Mobis Co. climbed 16.45%, Samsung Life Insurance Co. advanced 10.58%, Samsung C&T Corp. added 10.26%, and LG Electronics Inc. gained 9.17%.

The Kosdaq also rose more than 5%. As of that time, the index was up 5.08% at 1,109.75. A buy sidecar was also triggered on the Kosdaq in early trading. MachinaRocks, which debuted the previous day after quadrupling from its IPO price, surged to the daily limit again early on May 21.

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