Vanguard Institutional Index Fund Institutional Shares 

Seeks to track the performance of the Standard & Poor’s 500 Index, which measures the investment return of large-capitalization stocks.Follows a passively managed, full-replication approach.Provides a convenient way to match the performance of a substantial portion of the nation’s largest stocks.With respect to 75% of its total assets, the fund may not: (1) purchase more than 10% of the outstanding voting securities of any one issuer or (2) purchase securities of any issuer if, as a result, more than 5% of the fund’s total assets would be invested in that issuer’s securities; except as may be necessary to approximate the composition of its target index. This limitation does not apply to obligations of the U.S. government or its agencies or instrumentalities.