SK Hynix Sinks 5% as China’s CXMT Aims at Server Memory; Western Digital Drops 4%, Micron Falls 3%

SK Hynix (NASDAQ:SKHY) stock is down 5% to $148.70 as China’s ChangXin Memory Technologies (CXMT) signals it’s aiming a denser chip design at server memory. That push targets the most profitable corner of the memory market, and the selling is spreading across U.S.-listed names tied to AI data center buildouts. Memory and storage companies have delivered strong recent earnings, which puts pricing power at the center of the debate.

Meanwhile, Western Digital (NASDAQ:WDC | WDC Price Prediction) stock is down 4% to $364.04, a smaller drop than SK Hynix stock. Additionally, Micron Technology (NASDAQ:MU) stock is down 3% to $925.45, though it’s still up 223% year to date.

Selling is concentrated in the memory/storage segment. The Roundhill Memory ETF (CBOE:DRAM) is down 4%, and its latest fact sheet shows SK Hynix at 24.2% and Micron at 23.8% of the fund. By comparison, a broader tech fund, the Invesco QQQ Trust (NASDAQ:QQQ) is down just 2%.

China’s CXMT Takes Aim at Server Memory

Memory makers began selling off on October 12 after CXMT disclosed progress on a denser chip design. The slide has continued as CXMT points that capability at server memory, the highest-margin end of the market. SK Hynix stock has fallen 22% over the past month.

Its Q2 FY2026 preliminary revenue reached 79.32 trillion Korean won, up 256.8% year over year (YoY), with operating profit of 60.54 trillion won. A serious Chinese entrant threatens the premium pricing behind those gains.

HBM Makers and Storage Players Run on Different Timelines

SK Hynix and Micron make the high-bandwidth memory (HBM) that sits beside AI accelerators, putting CXMT’s server push directly in their territory. Western Digital has operated as a pure-play hard disk drive (HDD) company since separating its flash business in February 2025, leaving it a step removed.

Micron’s own results show how tight server memory remains. In fiscal Q4 2026, the company’s revenue reached $54.23 billion, up 379.3% YoY, with a non-GAAP gross margin of 87%. The company guided fiscal Q1 2027 revenue to $61.5 billion.

On the September 30 earnings call, CEO Sanjay Mehrotra stated, “As we noted, in calendar year 27 as well as 2028, we see demand exceeding supply. In fact, we see greater tightness in the industry in 27 and in 28 versus 26.” More than 75% of Micron’s 2027 output is already committed, and Micron has signed 26 Strategic Customer Agreements carrying take-or-pay volumes. The call made no direct reference to CXMT.

Western Digital’s latest quarter points to storage demand running on its own track. Its fiscal Q4 2026 revenue came in at $3.75 billion, up 43.8% YoY, while its non-GAAP gross margin expanded to 54.4%. CEO Irving Tan stated that “roughly 80% of data stored in a hyperscale data center resides on hard disk drives,” adding that the pattern is likely to continue.

Hyperscale Qualification Is CXMT’s Real Hurdle

The next test for SK Hynix is whether CXMT can get its server memory qualified by hyperscale customers, as HSBC reaffirmed the stock as a top chip pick earlier this year with HBM leadership central to that bull case.

Micron’s open variable is pricing on the 2027 output it has already committed. Management expects supply to stay tighter in calendar 2027 and 2028 than in 2026, so any hyperscaler shift toward CXMT would test that view.

Western Digital’s fiscal Q1 2027 results, guided to $4.1 billion in revenue, could show whether hyperscale storage demand remains protected from memory pricing. Position sizes should be kept small until CXMT’s server memory reaches customers.

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