S&P 500 Posts Worst Quarter Since Q3 2022 Amid heightened Iran tensions, growing stress in private credit, and a rotation out of AI-related names, large-cap equities struggled in Q1 2026. The S&P 500 Index declined 4.3%, marking its worst quarter since Q3 2022, while the tech-heavy Nasdaq 100 Index fell even further, down 5.8%. Meanwhile, the S&P 500 Equal Weight Index eked out a modest 0.7% gain. Despite a difficult March, other rotational pockets were able to hold onto gain