On Wednesday, stock indices recorded their worst day in more than 18 months, after lackluster earnings results from index heavyweights Tesla (TSLA) and Alphabet (GOOGL) deepened a technology sector sell-off. The S&P 500 Index ($SPX) fell 2.3%, its worst day since December 2022, while the tech-heavy Nasdaq Composite ($NASX) gave up 3.6% to record its worst day since October 2022. The losses in both were driven by the same Big Tech stocks — and artificial intelligence (AI) stocks, in particular — that have driven the bulk of the stock market’s gains this year. While many market observers say the…