Wall Street's main indexes closed higher on Monday, buoyed by a fresh wave of enthusiasm for artificial intelligence (AI) and ahead of a highly anticipated Federal Reserve meeting. The technology-heavy Nasdaq led the gains, supported by significant advances in megacap growth stocks such as Alphabet and Tesla. The optimism was partly fueled by Nvidia's major AI conference, which investors closely followed, alongside general anticipation for the Federal Reserve's policy decisions. This positive sentiment was reflected across various platforms, with S&P 500 and Nasdaq futures ticking up in premarket trading as investors balanced their hopes for AI advancements with concerns over potential rate hikes and awaited the Fed meeting.