Shares of leading U.S. semiconductor memory maker Micron Technology plunged 17.5% on 5 November local time. As selling spread across AI-related stocks, the filing of Form 8-K and the departure of an officer were disclosed that day, while Western Digital and AMD also posted share-price changes of roughly the same magnitude.
Micron Technology's share price plunged 17.5% on 5 November local time from the previous day's closing price, marking a sharp decline as the S&P 500 fell 4.4%. Market concerns had been mounting over the sustainability of AI infrastructure investment, including data centers, and the outlook for the cycle of surging memory prices.
That day, Micron filed Form 8-K, a current report, with the SEC and disclosed that one of its directors would leave the board. Selling extended beyond Micron to Western Digital, a major hard-disk-drive maker in the same industry, and semiconductor giant AMD.
Micron's revenue for the fourth quarter of fiscal 2026 was $54.2 billion, up 379.3% year on year, while gross margin improved significantly to 86.8%. At its earnings briefing, the company indicated that margins in fiscal 2027 were expected to exceed first-quarter levels from the second quarter onward.
Although the pace of price increases was expected to moderate, price increases themselves were expected to continue, which was seen as supporting margins.