The S&P 500 experienced a notable surge, closing over 100 points higher following a decline in core CPI inflation. This unexpected drop in inflation data contributed to a significant increase in market capitalization, with the S&P 500 adding $900 billion on January 15, 2025. Analysts noted that the index is on track for its strongest week since November 2024, having gained approximately $1.5 trillion in market cap over the past five days. In total, the S&P 500 has seen an increase of about $1.9 trillion in market capitalization over the last four days, signaling a robust market recovery.