AI memory chip stocks came under renewed pressure Thursday after a brutal selloff in South Korea sent SK Hynix and Samsung Electronics sharply lower, raising fresh questions about stretched valuations, future semiconductor capacity and the durability of the artificial intelligence spending boom.
South Korea’s KOSPI index closed down approximately 7.9%, with SK Hynix plunging about 14.6% and Samsung Electronics falling roughly 9.1%. Because the two memory-chip giants represent an unusually large portion of the benchmark, their declines had an outsized effect on the wider Korean market.
The pressure quickly spread to U.S.-listed memory and storage companies. Micron Technology shares fell in premarket trading after already dropping 10.6% during Wednesday’s session. SanDisk, Western Digital and other AI-linked hardware names also remained under pressure as investors continued rotating out of some of the market’s strongest first-half performers.
For investors, the central question is whether this is simply profit-taking after an extraordinary rally or the beginning of a deeper reassessment of AI infrastructure demand.
Why SK Hynix and Samsung Shares Plunged
The immediate catalyst was a broader retreat from semiconductor and AI-related stocks. Concerns intensified after reports that Meta Platforms was considering selling excess computing capacity, prompting investors to question whether some technology companies have built more AI infrastructure than they currently need.
The possibility of surplus cloud capacity matters for memory-chip producers because AI servers require large volumes of high-bandwidth memory, DRAM and NAND storage. If hyperscalers become more cautious about adding data-center capacity, demand expectations across the semiconductor supply chain could be revised lower.
Jefferies economist Mohit Kumar said concerns that technology companies may have overbuilt computing infrastructure were weighing on market confidence. Meta Chief Executive Mark Zuckerberg has previously acknowledged that selling unused computing resources could become an option if the company concludes that it has installed too much capacity.
However, the selloff also reflects the scale of the previous rally. SK Hynix shares had more than tripled during 2026 before Thursday’s decline, powered by the company’s leadership in high-bandwidth memory used in Nvidia and Google AI systems. Samsung and Micron also recorded enormous gains as investors priced in tight supply and rising memory prices.
When valuations and investor positioning become this extended, even modest doubts about future demand can lead to aggressive profit-taking.
Micron Stock Feels the Global Memory Selloff
Micron remains the clearest U.S. read-through from the Korean market decline. The company competes directly with SK Hynix and Samsung in DRAM and high-bandwidth memory, making its shares highly sensitive to changes in global memory sentiment.
Micron stock fell 10.6% to $1,032.28 on Wednesday and was down another roughly 2.4% in Thursday premarket trading, according to market reports. Despite the decline, the stock remained dramatically higher over the previous twelve months after investors embraced Micron as a major U.S. beneficiary of AI infrastructure spending.
The pullback does not necessarily mean Micron’s underlying business has weakened. DRAM prices rose approximately 3% in June, while NAND flash prices increased about 2.4%, supported by persistent data-center demand. KeyBanc analyst John Vinh has said major new industry capacity is not expected until 2027 and that supply conditions remain tight through 2026.
That creates a sharp contrast between the stock-market narrative and current industry fundamentals. Share prices are falling because investors fear what could happen to demand and supply in the future, not because current memory prices have already collapsed.
Massive Capacity Plans Raise Oversupply Fears
Longer-term supply expansion is another reason investors are becoming cautious. Samsung and SK Hynix have announced plans to invest a combined approximately 800 trillion won, or about $519 billion, in new semiconductor manufacturing hubs in South Korea.
SK Hynix separately announced a 100 trillion won, or roughly $64 billion, investment in new memory-chip manufacturing and packaging facilities. The program includes a NAND flash factory expected by 2029 and a packaging plant targeted for completion in late 2027.
Those investments demonstrate management confidence in long-term AI demand. They also create a familiar risk for memory investors: today’s shortages can encourage tomorrow’s oversupply.
The memory industry has historically moved through sharp boom-and-bust cycles. Strong pricing encourages producers to add capacity, but once new supply reaches the market, prices and margins can fall quickly. AI and high-bandwidth memory may make this cycle more durable than previous ones, but they do not eliminate supply risk entirely.
Investors are therefore trying to determine whether planned capacity will arrive alongside equally strong growth in AI inference, cloud computing and enterprise adoption—or whether suppliers could eventually build ahead of demand.
Does the Selloff Signal an AI Spending Slowdown?
The evidence is mixed.
On the bearish side, reports of excess cloud capacity raise concerns that some hyperscalers may be approaching a more disciplined phase of capital spending. If companies begin monetizing unused infrastructure rather than purchasing additional servers, demand growth for GPUs, networking equipment and memory could slow.
The broader rotation out of technology stocks also suggests that investors are becoming less willing to tolerate extreme valuations. Memory and storage names were among the strongest performers of the first half of 2026, leaving them vulnerable when market sentiment turned.
On the bullish side, physical memory markets remain tight. Analysts expect shortages in some NAND products to persist into mid-2027, while long-term customer contracts and prepayments are giving suppliers greater visibility than in previous cycles. Bank of America has argued that supply shortages should limit the downside for companies such as SanDisk.
Demand for AI training and inference also continues to require substantial memory capacity. High-bandwidth memory uses more wafer capacity than traditional DRAM, potentially limiting how quickly producers can increase total supply.
The current decline therefore looks more like a valuation and positioning reset than clear evidence that AI memory demand has collapsed.
Why the KOSPI Was Hit So Hard
South Korea’s stock market is especially exposed to the semiconductor cycle. Samsung and SK Hynix together account for a large share of the KOSPI’s market capitalization, meaning sharp moves in the two companies can dominate the index.
Earlier in 2026, their AI-driven rallies helped make the KOSPI one of the world’s strongest-performing equity benchmarks. That concentration works in both directions. When memory stocks rise, the index can surge. When they fall simultaneously, the broader market can experience unusually severe losses.
Leveraged exchange-traded products and heavy retail positioning may have amplified Thursday’s move. Selling in leveraged semiconductor vehicles can create additional pressure as funds rebalance exposure during periods of extreme volatility.
The decline also spread across Asia. Japanese memory-chip producer Kioxia fell more than 13%, while the Nikkei 225 dropped around 2.5%, showing that concerns extended beyond South Korea.
What Investors Should Watch Next
The first issue is whether hyperscalers actually reduce AI capital spending. Reports of excess computing capacity are important, but confirmed changes to spending plans from Meta, Microsoft, Alphabet, Amazon and Oracle would carry more weight.
The second is memory pricing. Continued strength in DRAM, NAND and HBM prices would suggest that current demand remains healthy despite falling stock prices.
The third is supply expansion. Investors should monitor factory timelines from Samsung, SK Hynix and Micron, particularly whether new capacity arrives faster than expected.
The fourth is customer contracts. Long-term agreements, prepayments and sold-out capacity can reduce the traditional cyclicality of the memory industry.
Finally, investors should watch whether the selloff stabilizes or spreads further into Nvidia, AMD, Broadcom and semiconductor-equipment stocks. A contained memory correction would have different implications than a broader repricing of the entire AI infrastructure trade.
Bottom Line: AI Memory Fundamentals Face a Valuation Test
The sharp declines in SK Hynix, Samsung and Micron show that investors are no longer willing to assume the AI memory boom will continue without interruption. Concerns about excess computing capacity, huge manufacturing investments and extraordinary stock gains have created the conditions for a severe correction.
Yet the fundamental picture remains more resilient than the share-price action suggests. Memory prices are still rising, supply remains constrained and AI data centers continue to require substantial quantities of HBM, DRAM and NAND.
That makes the selloff a critical test. If demand remains strong and shortages persist, the decline may ultimately look like a reset after an overheated rally. If hyperscaler spending slows while new production capacity accelerates, the market could be signaling the return of the memory industry’s familiar boom-and-bust cycle.
FAQ
Why are AI memory chip stocks falling?
AI memory chip stocks are falling because investors are taking profits after a major rally and questioning whether technology companies have built excess computing capacity. Concerns about future semiconductor supply are also weighing on sentiment.
How much did SK Hynix and Samsung fall?
SK Hynix dropped approximately 14.6%, while Samsung Electronics declined around 9.1% during Thursday’s trading in South Korea.
Why is Micron stock affected by the KOSPI selloff?
Micron competes directly with SK Hynix and Samsung in DRAM, NAND and high-bandwidth memory. Weakness in the Korean memory sector often affects expectations and trading sentiment around Micron stock.
Is AI memory demand slowing?
There is not yet clear evidence of a broad collapse in demand. Memory prices remain firm and supply is still tight, but investors are worried that hyperscalers may slow future data-center spending if they have excess computing capacity.
Could new factories cause a memory-chip oversupply?
Yes. Large capacity investments from Samsung, SK Hynix and Micron could eventually pressure prices if supply grows faster than AI and data-center demand. However, much of the newly announced capacity will not arrive for several years.
Disclaimer: This article is for informational purposes only and does not constitute financial advice. Always conduct your own research before making any investment decisions.
