Mu Stock fell about 11% on Tuesday after a report said SK Hynix was slowing its high-bandwidth memory expansion, and the selling spread fast through the semiconductor trade. SK Hynix and Samsung each dropped more than 12% in Asia, while the KOSPI fell about 10% and triggered a 20-minute market-wide circuit breaker.
That reaction is why traders were searching the name so quickly. Micron had already climbed about 300% since the start of the year, so the pullback landed after an enormous run, not after a weak one. On Wall Street, the Philadelphia Semiconductor Index opened down roughly 7% a day after closing at a record high, and Applied Materials, Teradyne and Entegris also fell, with Entegris off 9.4% and the others down 8.3% each.
The move mattered because the selling was broad enough to hit the whole AI-chip complex, even though the latest report pointed to margins, not demand. Micron had just added 7% to 8% five days earlier after a wave of analyst price target hikes, and Stifel, Wedbush, Deutsche Bank and TD Cowen all lifted their models sharply higher. That followed a period when Samsung said DRAM average selling prices jumped 146% in the first quarter and SK Hynix reported mid-60% gains, numbers that show how tight memory supply still is. In other words, the headline looked like a warning that AI spending was cooling, but the underlying story was that SK Hynix is said to be slowing its HBM4 ramp to shift capacity back into conventional DRAM.
That is the friction in the trade: a margin story got read like a demand story. Wedbush called the drop a buying opportunity and said enterprise demand remains intact, which matches the pricing power still visible in the memory market. Traders are also parsing other forces around the move, including President Trump’s announcement that Apple had agreed to design and manufacture chips with Intel in the United States and the separate view that markets were pricing 50 basis points of Fed hikes by December under Chair Kevin Warsh. The short-term question is not whether Micron still has momentum; it is how long SK Hynix keeps throttling HBM expansion before the market decides the selloff was overdone.
