The U.S. stock market experienced a downturn today, with the S&P 500 index declining by 1.36%. Over the past five days, the index has seen a slight decrease of 0.11%, while its performance over the last 30 days reflects a more significant drop of 3.73%. In terms of market capitalization, the advance-decline ratio indicates a challenging environment, with 829 stocks advancing compared to 3,287 declining, resulting in an overall ratio of 0.25. Large-cap stocks fared particularly poorly, with only 38 advancing against 195 declining, yielding a ratio of 0.19. Mid-cap stocks showed a similar trend, with 41 advancing and 220 declining. Small-cap stocks had a slightly better performance, with 263 advancing but still facing 1,180 declines. Among individual stocks, Cloudflare, Inc. emerged as the best performer in the large-cap category, posting a return of 6.6%. Conversely, Carvana Co. struggled, recording a return of -7.49%. In the mid-cap sector, LyondellBasell Industries NV led with a return of 5.62%, while Otis Worldwide Corp. fell by 6.67%. Small-cap stocks saw Microvast Holdings, Inc. rise by 13.16%, while QuidelOrtho Corp. faced a decline of 10.93%. Overall, the market reflects a challenging landscape for investors, with a significant number of stocks underperforming.