Why bank stocks fell

The S&P 500 bank index, a basket of stocks, fell 2.7% on Sept. 22, 2026, Reuters reported, on AI worries and a flattening yield curve. Schwab fell 6.1%, Ameriprise 4.4%, Reuters said. When long and short rates get closer, like a shop narrowing buy and sell prices, banks earn less, which can reach savers and borrowers.