Micron's Blockbuster Q4 Outlook Sends Tokyo AI Stocks Soaring

Micron Technology's stronger-than-expected fiscal Q4 earnings and forward guidance ignited a wave of concentrated buying across Japan's artificial intelligence and semiconductor sectors on October 1, with the Nikkei 225 Index momentarily climbing to 68,900 yen on heavy gains in chipmaker and chip-equipment stocks. The U.S. memory chipmaker reported fiscal fourth-quarter revenue of $54.23 billion, more than quadrupling year-over-year levels, and guided first-quarter revenue to $61.5 billion—well above analyst expectations. The results underscored relentless demand for high-bandwidth memory tied to AI infrastructure buildout globally. Micron noted that customers had increased long-term supply commitments to $32 billion, signaling sustained momentum in AI data center procurement. Gross profit margin expanded to 87%, reflecting unprecedented pricing power in the memory market driven by AI optimization needs. For the full fiscal 2026, Micron posted revenue of $133.19 billion and net income of $84.97 billion, a dramatic turnaround from the prior year's $37.38 billion in revenue. The semiconductor sector's outperformance on October 1 reflected investor confidence that AI infrastructure investment globally will continue driving demand for advanced chip technologies. Tokyo Electron contributed significantly to the day's gains, along with index heavyweight SoftBank Group. Test equipment maker Advantest gained 7%, signaling optimism about sustained chip capital spending. However, market breadth remained narrow—declines outnumbered advances, with the broader Topix index gaining just 0.03%—suggesting the rally remained concentrated among a handful of favored AI-enabled companies rather than representing broad-based market strength. The muted broader market performance underscored how AI-related gains have bifurcated Japan's equities, with semiconductor and AI-linked shares commanding disproportionate investor attention amid global AI deployment acceleration.