SPY closed September 15 2026 at 757.39 against 762.40 on September 9 (-0.7%), QQQ at 704.54 against 716.31 (-1.6%) and IWM at 285.14 against 290.64 (-1.9%). For the first time in three refreshes the Nasdaq-100 led the decline rather than cushioning it, and small caps extended a divergence now running four consecutive windows.