SK Hynix Hits Daily Limit for First Time Since 2009; Samsung Electronics Soars 26%

AI optimism and easing deleveraging spur buying

Foreign investors snap up 7 trillion won ($5.05 billion) in Kospi spot market

SK Hynix closed at its daily upper limit for the first time since 2009 as investors viewed the recent selloff in semiconductor shares as overdone. Samsung Electronics also surged more than 26%.

SK Hynix ended July 31 up 29.95% from the previous session at 1,718,000 won. After jumping more than 20% early in the day, the stock hit the daily upper limit of 1,718,000 won at about 2:10 p.m.

It was the first time SK Hynix had reached its daily limit since Jan. 28, 2009. It was also the first such move since South Korea expanded the Kospi's daily trading band to plus or minus 30% from plus or minus 15% in 2015.

SK Square, the largest shareholder of SK Hynix with a 20% stake, also finished at its daily limit, rising 29.91% to 1,038,000 won.

Samsung Electronics climbed 26.81% to close at 262,500 won. Samsung Electronics preferred shares gained 26.49%.

The sharp rally in SK Hynix and Samsung Electronics was driven by stronger risk appetite after solid earnings from US Big Tech revived expectations for expanded artificial intelligence spending. A growing view that recent deleveraging had largely run its course also helped fuel foreign buying. Overseas investors were net buyers of 7 trillion won ($5.05 billion) in the Kospi spot market alone on July 31.

Microsoft's stronger-than-expected earnings also lifted sentiment, easing some doubts over the durability of AI investment.

Microsoft said Azure revenue in its fiscal 2026 fourth quarter, covering April through June, rose 43% from a year earlier, the fastest growth rate since early 2022. The company also maintained its existing capital expenditure plan for fiscal 2026.

A view that global semiconductor stocks had fallen too far also supported sentiment. The Philadelphia Semiconductor Index rose more than 8% overnight in New York, while SK Hynix's American depositary receipts listed in the US jumped more than 17%, recovering to their offering price. Memory and storage companies also rallied, with Micron Technology up 18.36%, SanDisk up 25.99% and Western Digital up 15.37%.

News of share purchases by SK Group Chairman Chey Tae-won added to investor confidence. SK Group disclosed a day earlier that Chey had bought 3,620 SK Hynix common shares during the session for a total of 4.9 billion won ($3.54 million), or about 1.35 million won per share. Following July 31's rally, he is estimated to have recorded a paper gain of about 1.3 billion won ($939,000) in a single day.

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