The Financial Post reports in its Tuesday, Aug. 12, edition that the S&P 500 is often viewed as a diversified benchmark, representing a broad cross-section of the U.S. economy. The Post's Martin Pelletier writes that today, however, that perception is increasingly misleading. The index has never been more concentrated in just a few names which introduces risks for investors. Nvidia alone represents nearly 8 per cent of the S&P 500, the highest weighting for a single stock in the index's history. Nvidia and Microsoft together account for nearly 15 per cent, and adding Apple brings the top three to 21 per cent. The top 10 stocks now make up a record 40 per cent of the index, surpassing the 27 per cent peak seen during the dot-com bubble in 2000. Yet these companies only generate about 30 per cent of the index's total earnings, highlighting a growing disconnect between price and fundamentals. When a few companies dominate index performance, it can create an illusion of market strength while masking underlying vulnerabilities. In a diversified market, a single company's negative news generally stays contained. However, in today's environment, a setback from one of these giants can cause widespread volatility.