Why did South Korean stocks rise nearly 6 percent on Wednesday morning?

Investor sentiment toward South Korean chipmakers was supported by overnight gains in U.S. technology shares, including a 3.6 percent rise in the Philadelphia Semiconductor Index. SK hynix also reported record third-quarter revenue and operating profit and announced additional shareholder returns.

How did major Korean stocks and the won perform during the Wednesday morning rally?

Samsung Electronics rose 7.77 percent, SK hynix gained 7.76 percent, SK Square advanced 8.7 percent and Samsung Electro-Mechanics surged 9.16 percent. The won traded at 1,336.0 per dollar, 9 won weaker than at the previous session’s close.

Seoul stocks up nearly 6% Wednesday morning on SK hynix earnings

Q: What triggered the Korea Exchange’s buy-side sidecar during the KOSPI rally?

The exchange activated the measure as the rally gathered momentum. It suspends buy orders in program trading for KOSPI-listed shares for five minutes when KOSPI 200 futures rise at least 5 percent and remain at that level for one minute or longer.

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Summary

South Korean stocks surged in Seoul late Wednesday morning, with the KOSPI up 5.8 percent to 5,965.13 as of 11:20 a.m., after SK hynix reported record quarterly earnings and announced additional shareholder returns. The Korea Exchange activated a buy-side sidecar, suspending program-trading buy orders for KOSPI-listed shares for five minutes. Samsung Electronics and SK hynix shares each rose more than 7 percent. The won traded at 1,336.0 per U.S. dollar, down 9 won from the previous session’s close.

Key Facts

The KOSPI gained 326.79 points after opening 2.23 percent higher.
The sidecar is triggered when KOSPI 200 futures rise at least 5 percent and stay at that level for one minute or longer.
SK hynix attributed its record third-quarter revenue and operating profit to robust memory chip demand.
SK hynix announced a shareholder return program worth more than 100 trillion won for 2026.
Ahead of the Federal Reserve’s rate decision scheduled for early Thursday Korean time, investors were looking for signals about the future path of U.S. interest rates.

By Yonhap

Published Oct 28, 2026 9:30 am KST
Updated Oct 28, 2026 11:38 am KST

The KOSPI and Kosdaq indices can be seen on a screen at a dealing room of Hana Bank in Seoul, Wednesday. Yonhap

Korean stocks surged nearly 6 percent late Wednesday morning, led by a rally in chipmakers after SK hynix reported record quarterly earnings and announced additional shareholder returns.

After opening 2.23 percent higher, the benchmark Korea Composite Stock Price Index (KOSPI) extended its earlier gains to trade up 326.79 points, or 5.8 percent, to 5,965.13 as of 11:20 a.m.

As the rally gathered momentum, the Korea Exchange activated a buy-side sidecar shortly before 10 a.m., suspending buy orders in program trading for KOSPI-listed shares for five minutes.

The measure is triggered when KOSPI 200 futures rise at least 5 percent and remain at that level for one minute or longer.

Overnight, U.S. stocks extended their gains, led by a rally in artificial intelligence (AI)-related technology shares.

The tech-heavy Nasdaq Composite climbed 1.18 percent, while the Philadelphia Semiconductor Index jumped 3.6 percent, boosting investor sentiment toward South Korean chipmakers.

Earlier in the day, SK hynix reported record-high revenue and operating profit for the third quarter on robust memory chip demand and announced a shareholder return program worth more than 100 trillion won ($75.3 billion) for 2026.

Meanwhile, investors remained cautious ahead of the Federal Reserve's rate decision scheduled early Thursday (Korean time), looking for signals on the future path of U.S. interest rates.

KOSPI heavyweights rose across the board.

Market bellwether Samsung Electronics advanced 7.77 percent, and chip giant SK hynix increased 7.76 percent.

SK Square, the parent firm of SK hynix, jumped 8.7 percent, and Samsung Electro-Mechanics, an electronics component affiliate of Samsung Electronics, surged 9.16 percent.

The Korean won was trading at 1,336.0 won against the U.S. dollar at 11:20 a.m., down 9 won from the close of the previous stock trading session.

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