SK Hynix shares surge 25%, while Samsung soars over 20% as AI rally roars back

South Korea's chip heavyweights SK Hynix and Samsung Electronics skyrocketed in Seoul on Friday, tracking a sharp rally in U.S. technology stocks after blockbuster earnings from Amazon and Microsoft revived optimism around artificial intelligence spending. SK Hynix was last trading over 25% higher, putting it on course for its best day on record if gains hold. Samsung rose more than 20%. LG Innotek advanced 11.2% and Seoul Semiconductor rose 7.8%. Japanese chip stocks also rallied sharply. Advantest, climbed nearly 18%, while Tokyo Electron gained almost 9%, Disco rose over 13%, Lasertec advanced more than 12% and Renesas Electronics added over 10%. SoftBank Group, a key artificial intelligence proxy as its owns Arm, also jumped more than 9%. The chip rally in Asia marks a sharp reversal from this week's bruising sell-off, as semiconductor stocks were battered by concerns over lofty AI valuations and signs of intensifying competition from Chinese memory chipmakers. The iShares Semiconductor ETF (SOXX) surged more than 8% overnight, as investors piled back into AI-linked chipmakers following stronger-than-expected cloud results from the two U.S. tech giants. Amazon jumped more than 9% in extended trading after reporting second-quarter revenue that beat analysts' expectations, driven by continued strength in its cloud-computing business. Microsoft had rallied 16% during Thursday's regular session after reporting faster-than-expected Azure cloud growth, reinforcing confidence that AI infrastructure spending remains robust. Andrew Jackson, head of equity strategy at Ortus Advisors, said Microsoft's stronger-than-expected quarterly results "sparked a huge rebound for risk-on and AI," helping reverse the recent sell-off in technology stocks. He wrote in a note on Friday that investors were reassured after Azure cloud revenue beat expectations while management kept capital spending "in check," noting that a "'spend at all costs' mentality has been punished by the market."