US stocks ended lower on Friday, marking weekly and monthly losses amid mixed economic data and concerns over Federal Reserve policy. The S&P 500 and Dow Jones Industrial Average both declined, with the Nasdaq Composite showing the steepest drop due to tech sector weakness. The sell-off reflects investor caution ahead of key inflation data and potential rate hike signals from the Fed. The decline pressures global markets, including emerging economies like Saudi Arabia, which may face capital outflows and reduced foreign investment.