Vanguard Mid-Cap Index Fund Institutional Plus Shares 

This economical index fund offers extensive exposure to U.S. companies with medium market capitalizations. Its primary objective is to mirror the performance of an index comprising such mid-sized enterprises, whose stock prices often exhibit more significant fluctuations compared to larger corporations. Consequently, this elevated market volatility represents a principal risk associated with the fund. It is an ideal consideration for investors seeking to integrate a passively managed allocation to mid-cap equities into an already diverse investment portfolio.