Vanguard Morningstar Mid-Cap Index Fund Institutional Shares 

This economical index fund offers extensive exposure to mid-sized American companies. Its primary objective is to replicate a benchmark index composed of firms with moderate market capitalizations. Equities from these enterprises typically exhibit greater price fluctuations compared to those of larger corporations, and this inherent volatility represents a significant risk for the fund. Investors aiming to incorporate a passively managed, mid-capitalization stock allocation into an already diversified investment portfolio may find this fund to be a suitable option.