S&P 400

The S&P 400 is a market-capitalization-weighted index that tracks 400 U.S. mid-cap companies across diverse sectors. It provides a representative snapshot of the mid-cap segment, often considered a balance between the stability of large-cap firms and the growth potential of small caps. The index is frequently used by investors to gauge the health and performance of medium-sized enterprises, which play a critical role in economic expansion and sector innovation. Compared to the S&P 500 or S&P 600, the S&P 400 offers targeted exposure to firms with established operations and moderate growth trajectories.