SK Hynix surges 30% to daily limit as Kospi jumps 18%

SK Hynix surged 29.95% to 1.718 million won on Friday, hitting its first-ever daily limit, as South Korea's Kospi jumped 17.9% to 6,695.45 in its largest single-day gain on record. The stock opened 28.37% higher at 1.697 million won and climbed to the exchange's 30% daily cap, a limit raised from 15% in June 2015.

The rebound was "more repair than reset," said Patrick Munnelly, market analyst at Tickmill, noting that aggressive short-covering in a deeply oversold market drove the move rather than a full restoration of confidence.

Samsung Electronics surged 28% to 265,000 won, while the Kospi's 17.9% jump eclipsed the previous record of nearly 12% set in October 2008 during the global financial crisis. The benchmark still ended July down 22%, its worst monthly decline since the 23% plunge in October 2008, and sits about 30% below its June peak above 9,000.

The rally followed stronger-than-expected cloud earnings from Microsoft and Amazon, which sent the iShares Semiconductor ETF up 8.5% overnight. Microsoft shares soared 15.5% for their best day in nearly 18 years, while Amazon climbed more than 9.5% in after-hours trading after raising its 2026 capital expenditure projection from $200 billion to $220 billion.

Volatility risk remains elevated

The Kospi's wild swings this month exposed the market's dependence on just two companies. Samsung Electronics and SK Hynix account for a disproportionate share of the benchmark's weight, and retail investors piled into leveraged single-stock ETFs linked to both names after their May launch — just weeks before the AI rally peaked. Those products forced daily rebalancing into falling markets, deepening the selloff.

SK Hynix reported record second-quarter results on Wednesday, with operating profit rising 557% year over year to 60.54 trillion won (about $43.2 billion), though that missed the 64 trillion won analysts expected. Revenue more than tripled to a record 79.32 trillion won, while the company posted a 76% operating margin. SK Group Chairman Chey Tae-won bought 3,620 shares for 4.9 billion won ($3.41 million) a day before the surge, a purchase that gained roughly 1.3 billion won ($904,000) in value within a single session.

Wolfe Research analyst Chris Caso remains bullish on memory stocks, saying tight supply and strong AI-driven demand support the sector, with meaningful oversupply unlikely before 2028 given the time required to build new chip manufacturing capacity.

Across Asia, the rebound was broad. Japan's Nikkei 225 climbed 4% to 64,362.02, with SoftBank Group jumping 13.8% and Tokyo Electron rising 6.2%. Taiwan's Taiex surged 8%, helped by a 10% jump for TSMC. The dollar gained 0.5% to 160.28 yen, while Brent crude traded at $87.50 a barrel.

SK Hynix's U.S.-listed American depositary receipts climbed 6.20% in premarket trading Friday, tracking the Seoul surge, and later traded up about 7.1%.

The question for investors is whether Friday's surge marks a genuine bottom or a short-term reprieve. With the Kospi still 30% below its June peak and leveraged retail products amplifying moves in both directions, volatility is likely to remain elevated in the weeks ahead.

This article is for informational purposes only and does not constitute investment advice.