U.S. stock markets experienced a decline ahead of the Federal Reserve's interest rate decision, with the S&P 500 down 0.9% as Fed Chair Jerome Powell began his press conference. Following Powell's remarks, stocks continued to slide, culminating in a significant drop for Wall Street. The market closed sharply lower after the Fed's announcements, reflecting investor concerns over the central bank's monetary policy direction. The volatility underscores the ongoing uncertainty in the financial markets as investors react to the Fed's decisions.