September has historically been the weakest month for stocks, but not in 2025. In fact, the entire third quarter has been a treat for investors, with U.S. equities marching to new highs and bouncing back from April's tariff tiff. Most of that optimism came as Q2 earnings surprised to the upside, the AI-fueled trade continued to gain momentum, and investors piled on the bets that the Federal Reserve would cut rates. Compounding existing excitement, earnings growth is expected to continue, AI optimism cont ...