The S&P 500 index experienced a decline of 0.55% today, although it has shown a notable increase of 2.94% over the past 30 days. In the large-cap segment, McKesson Corp. emerged as the top performer with a return of 6.36%, while Vistra Corp. lagged behind with a decline of 6.28%.
In the mid-cap category, Halliburton Co. led the way with a return of 7.34%, contrasting with Affirm Holdings, Inc., which saw a drop of 8.2%. The small-cap sector was dominated by ATAI Life Sciences NV, achieving a remarkable return of 14.96%, while Opendoor Technologies, Inc. faced a significant decline of 15.39%.

Overall, the advance-decline ratio across the market indicated that 1,646 stocks advanced compared to 2,367 that declined, resulting in a ratio of 0.7x. In large-cap stocks, 124 advanced against 109 that declined, yielding a ratio of 1.14x. Mid-cap stocks showed a balanced performance with 130 advancing and 130 declining, while small-cap stocks had 616 advancing and 854 declining, resulting in a ratio of 0.72x.