Sandisk is trading 3.5% up at $1803.38 after officially joining the S&P 100 before the September 21, 2026, open.

  • The inclusion can increase institutional visibility and demand, following Sandisk’s 10.99% gain on September 18.
  • Memory-chip stocks are rallying on renewed AI optimism, strong South Korean chip exports, and tight NAND supply.
  • Major U.S. indexes are higher, reinforcing the risk-on move.