SK Hynix Shares Surge Nearly 30% as Record KOSPI Rally Follows Microsoft's Blockbuster Earnings Beat

Shares of SK Hynix surged 29.95% on Friday, climbing 396,000 won to close at 1,718,000 won on the Korea Exchange, effectively hitting the exchange's daily limit for individual stock price movements as South Korea's benchmark KOSPI index posted the largest single-day rally in its history.

The KOSPI closed up 17.91% at 6,595.45, marking a record in both point and percentage terms, according to the Korea Herald. Samsung Electronics, SK Hynix's chief domestic rival in the global memory chip market, surged as much as 26.81% during the same session, according to TradingKey, as both of South Korea's dominant chipmakers effectively erased much of the ground they had lost during three brutal preceding trading sessions.

Friday's rally traced its origins directly to a powerful overnight session on Wall Street. Microsoft's shares soared 15.5% Thursday for the company's best single-day performance in nearly 18 years, according to the Associated Press, after the technology giant reported that its Azure cloud computing division grew 43% during the quarter, easing broader investor concerns about the sustainability of massive capital spending on artificial intelligence infrastructure. Amazon and Meta Platforms also posted results that exceeded market expectations, reinforcing confidence that AI-related computing demand remains robust, according to CNBC, sending a wave of optimism through Asian technology markets overnight.

SK Hynix's own recent earnings had already demonstrated the underlying strength driving Friday's rebound, even though the company's stock had initially sold off sharply following the results. SK Hynix reported record revenue of 79.3 trillion won for the second quarter, up 51% from the prior quarter and 257% from the same period a year earlier, alongside operating income of 60.5 trillion won. The company said DRAM prices rose approximately 30% during the quarter while NAND flash memory prices surged into the mid-50% range, pushing its operating margin to a record 76%. Despite those record results, SK Hynix shares had initially fallen because the figures came in below the elevated expectations investors had built up around AI-related chip demand, contributing to the broader selloff that gripped the KOSPI over the following days.

Friday's rebound followed a brutal stretch for Korean equities more broadly. The KOSPI had plummeted more than 17% over the three trading sessions preceding Friday, driven by investor concerns about a potential bubble in artificial intelligence valuations and intensifying competition from Chinese chipmaking rivals, according to the Associated Press. At one point during that selloff, the index had fallen roughly 40% from its June peak, wiping out nearly $2 trillion in market value, according to reporting from the Private Banker.

Foreign investors were the driving force behind Friday's historic rebound, posting net purchases of 7.25 trillion won, or roughly $5.06 billion, on the KOSPI, according to the Korea Herald. That marked a second consecutive day of net foreign buying, following four straight sessions of net selling that had preceded Thursday.

A separate development specific to SK Hynix appeared to reinforce Friday's rally. SK Group Chairman Chey Tae-won disclosed personal purchases of SK Hynix shares during the recent selloff, a move that bolstered investor confidence in the world's second-largest memory chipmaker, according to CNBC, offering a visible signal of leadership confidence at a moment when the stock had come under significant pressure. New cash-deposit requirements for investors using leveraged exchange-traded funds also took effect July 31, a regulatory change some analysts said may have contributed to a broader repositioning among traders active in that segment of the market, while short-covering and mechanical rebalancing tied to leveraged ETFs were also cited as factors amplifying the scale of Friday's move.

SK Hynix has continued advancing its next-generation memory technology even amid the recent share price volatility. The company said it had begun mass production of its HBM4 high-bandwidth memory chips, with a broader production ramp planned for the second half of 2026, and that it had secured long-term supply agreements with approximately 10 customers as it works toward volume production of its subsequent HBM4E chips in 2027.

Despite the historic single-day gain, market analysts urged caution about reading too much into the rebound. Speaking to CNBC, one analyst identified only as Jung said foreign investors appeared to be the primary force behind Friday's rally, but cautioned against assuming the gains signal a durable trend reversal. "I would not expect gains of this magnitude to continue," Jung said, adding that asset prices had become "completely disconnected" from underlying fundamentals during the recent volatility.

Even after Friday's rally, the KOSPI remained well below its levels from earlier in the year. The index recorded its worst monthly performance since 1997, dropping 22.19% over the course of July, according to TradingKey, underscoring that Friday's rebound, while historic in scale, only partially offset the scale of losses the index had absorbed over the preceding weeks.

South Korean authorities also announced new measures Friday aimed at supporting the country's technology and artificial intelligence sector more broadly. The government said it would inject a minimum of 20 trillion won, or approximately $13.9 billion, into the Korea Investment Corporation for strategic investments in artificial intelligence, data centers and broader infrastructure, according to the Private Banker, marking the first time the sovereign wealth fund's mandate has been expanded to include domestic assets.

With SK Hynix shares having now hit the exchange's daily trading limit and the broader KOSPI having posted its largest single-day gain on record, investors are likely to watch closely in the sessions ahead for signs of whether Friday's rebound marks a genuine stabilization in sentiment toward AI-linked technology stocks or another dramatic swing within a period of extraordinary volatility that has gripped South Korea's chip-heavy equity market throughout the second half of July.