The S&P 500 experienced a notable decline, falling by 1.51% today and down 1.9% over the past five days. Over the last month, the index has dropped by 5.83%, reflecting a challenging environment for investors. In the large-cap sector, Marsh & McLennan Cos., Inc. emerged as the top performer with a return of 3.26%, while Vistra Corp. struggled significantly, posting a loss of 12.76%. Mid-cap stocks saw LPL Financial Holdings, Inc. lead with a gain of 2.71%, contrasting sharply with Super Micro Computer, Inc., which faced a steep decline of 33.32%. Small-cap stocks were highlighted by Planet Labs PBC, achieving an impressive return of 25.48%. However, Applied Optoelectronics, Inc. lagged behind with a loss of 14.11%. Overall, the advance-decline ratio across the market showed 1,001 stocks advancing against 3,283 declining, resulting in a ratio of 0.3x. In large caps, 52 stocks advanced while 181 declined, yielding a ratio of 0.29x. Mid caps had 56 advancing and 205 declining (0.27x), and small caps reported 244 advancing versus 1,195 declining, resulting in a ratio of 0.2x.