Micron Technology is trading 8.2% up now at $221, driven primarily by a memory-chip rally amid renewed AI optimism, strong South Korean chip-export data, and persistent DRAM and NAND supply tightness.
- The broader risk-on backdrop is supportive: S&P 500 up 0.79% and Nasdaq Composite up 1.29%.
- No new company-specific announcement was identified for September 21, 2026; the move is primarily sector-driven.