Live: Nasdaq falls more than 2% for worst day since June as AI spending woes, oil prices spark sell-off [https://www.cnbc.com/2026/10/21/stock-market-today-live-updates.html?__source=iosappshare%7Ccom.apple.UIKit.activity.CopyToPasteboard](https://www.cnbc.com/2026/10/21/stock-market-today-live-updates.html?__source=iosappshare%7Ccom.apple.UIKit.activity.CopyToPasteboard)