South Korea’s chip heavyweights staged their most violent one-day reversal in memory on Friday, with SK Hynix climbing more than 25 percent and Samsung Electronics advancing over 20 percent in Seoul. The move erased a week of losses driven by doubts about whether artificial intelligence infrastructure spending could justify the sector’s valuation premium, and it dragged the rest of Asia’s semiconductor complex higher in its wake.
The numbers are historic
SK Hynix’s gain puts the memory maker on track for its best single session on record if the advance holds through the close. LG Innotek added 11.2 percent and Seoul Semiconductor rose 7.8 percent. In Tokyo, the rally was nearly as broad: Advantest jumped almost 18 percent, Disco rose over 13 percent, Lasertec advanced more than 12 percent, Renesas Electronics gained over 10 percent and Tokyo Electron climbed nearly 9 percent. SoftBank Group, held as a proxy for its Arm stake, rose more than 9 percent. The iShares Semiconductor ETF surged over 8 percent overnight in U.S. trading.
The catalyst was cloud, not chips
The reversal traces directly to two U.S. earnings reports. Microsoft rallied 16 percent on Thursday after Azure cloud growth beat expectations while management signaled capital spending would remain “in check”, a phrase that Andrew Jackson, head of equity strategy at Ortus Advisors, said “sparked a huge rebound for risk-on and AI.” Amazon followed with a more than 9 percent jump in extended trading after its own cloud revenue exceeded forecasts. The market’s read: hyperscalers are still buying, but they are no longer writing blank checks.
The sell-off had a logic
That distinction matters. The preceding rout was not pure panic; it reflected a genuine reassessment of whether AI capex would grow at the exponential rates priced into semiconductor multiples. Concerns about Chinese memory competitors adding supply into a potentially softening demand picture compounded the pressure. Friday’s rally is a bet that the “spend at all costs” phase has been replaced by something more disciplined, and that discipline, perversely, is what keeps the spending sustainable.
What to watch next
The test now is whether cloud providers maintain this pace without the revenue acceleration that would justify it. Azure’s beat came with a capex signal that the market chose to read as prudence; the next quarter will reveal whether it was merely a pause. For SK Hynix and Samsung, the memory cycle still turns on utilization rates and pricing power, neither of which was resolved by a single earnings week. The record day is real. The trend change is not yet proven.