Nvidia's stock surge, which has risen 140% this year, significantly influences the S&P 500, accounting for a quarter of its 17% gain. The tech giant's 8.2% increase on Wednesday alone contributed to a major market rally, reversing earlier losses for the S&P 500 and aiding gains across major indices. Investors are closely monitoring inflation data, with lower-than-expected consumer prices bolstering expectations for an interest rate cut by the Federal Reserve at its upcoming meeting. The Consumer Price Index showed a notable drop to 2.5% year-over-year in August, encouraging momentum in tech stocks, particularly Nvidia, which has gained 13% in just three days. Amidst these developments, concerns loom over the reliance on a few tech stocks to drive broader market performance, with analysts cautioning that any weakness in Nvidia could significantly impact the market. Overall, the market sentiment is cautiously optimistic as it prepares for potential monetary policy shifts from the Fed.