Key TakeawaysThe S&P 500 ended 0.3% lower on Wednesday, Sept. 18, as the Federal Reserve announced its first interest-rate cut since March 2020.ResMed shares tumbled after analysts said the likely label expansion of popular weight-loss drugs to treat sleep apnea could hurt demand for the company's devices.General Motors stock increased as the carmaker introduced adapters allowing drivers to power up GM EVs using Tesla's charging station network. Major U.S. equities indexes ended lower on Wednesday after the ...