Key Takeaways The S&P 500 was essentially flat on Tuesday, Sept. 17, 2024, closing less than 0.1% higher on the last day before the Fed's key rate announcement. Enphase Energy shares soared after the solar tech firm launched a new home battery product and energy management software. Shares of Accenture lost ground amid reports that the consultancy firm will push back employee promotions to June from December. Major U.S. equities indexes finished little changed on the final trading day before the Federal Res ...