The Nasdaq Composite closed up 1.3% at 26,206.89 on Thursday, with the S&P 500 adding 0.81% to 7,543.65, as chip stocks swung back into favour less than a fortnight after the sector's steepest sell-off in months.
Micron Technology captured the volatility in miniature, touching an intraday gain of roughly 9% before giving back most of it to close up 4.5%, still enough to lead a broader rally across memory and AI-related stocks that also lifted SanDisk, Western Digital, Marvell, Broadcom, Intel and AMD.
Barely two weeks earlier, memory and chip stocks suffered a fear-driven semiconductor sell-off that erased US$2.7 trillion in market capitalisation from some of the biggest AI winners of the past year.
Micron had shed roughly 25% from its late-June peak, and Samsung lost more than $100 billion in market value despite posting a record profit, with weakness extending across Asian chip markets more broadly.
Three separate reports explain the week's turnaround, and none of them involved anyone actually buying more chips.
Hynix to debut
The catalyst sat in New York rather than Seoul, where demand for SK Hynix's U.S. share sale ran at seven times the available shares, giving Wall Street its clearest read yet on institutional appetite for memory exposure.
The company priced its American depositary receipts at $149 late Thursday, a premium to its Seoul-listed shares, which had closed the session up 5.3% at 2.186 million won (roughly $1,445), in a deal set to raise roughly $28 billion.
Temporary trading in SKHYV begins Friday on a when-issued basis, with regular trading under the ticker SKHY not starting until Monday, 13 July.
Micron accelerates spending
Micron supplied the second factor on Thursday, lifting its planned U.S. investment to more than $250 billion through 2035, up from the $200 billion pledge it made only last year.
"Data and memory are foundational to the modern economy," Micron chairman, president and chief executive Sanjay Mehrotra said.
The commitment includes up to $3 billion for the domestic semiconductor supply chain, part of which will fund GlobalWafers' wafer manufacturing facility in Sherman, Texas, under a newly signed 10-year supply agreement.
The expansion supports Micron's goal of producing 40% of its DRAM domestically, and follows the first concrete pour at its Clay, New York campus, a milestone reached more than a quarter ahead of schedule.
The Samsung effect
Underpinning the whole complex is Samsung's earnings guidance, with the world's largest memory maker expecting second-quarter operating profit of approximately 89.4 trillion won (around $59 billion), roughly 19 times higher than a year earlier.
That scale of growth underlines the pricing power built into this cycle.
Conventional DRAM contract prices rose 93 to 98% quarter-on-quarter in the first quarter of 2026, TrendForce data shows, followed by a further 58 to 63% in the second.
What to watch:
- SKHY's first full session on Monday, alongside GraniteShares' 2x long and short products, SKUU and SKDD, launching the same day.
- A federal class-action lawsuit filed in California, alleging Samsung, SK Hynix and Micron coordinated to restrict conventional DRAM supply while diverting capacity to HBM, with commodity memory prices up roughly 700% over four years according to the complaint.
- Whether June's doubters return, after the Bank for International Settlements warned in late June that the AI infrastructure boom could seed the next financial crash.
- SK Hynix's roughly 58% share of the global HBM market, and whether device makers keep absorbing higher memory costs without pushing back on volumes.
