Certification Pursuant to 18 U.S.C. Section 1350,
As Adopted Pursuant to
Section 906 of the Sarbanes-Oxley Act of 2002
Name of Issuer: Vanguard Institutional Index Funds
In connection with the Report on Form N-CSR of the above-named issuer that is accompanied by this certification, the undersigned hereby certifies, to his knowledge, that:
1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and
2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the issuer.
Date: August 12, 2009
/s/ F. WILLIAM MCNABB III |
F. WILLIAM MCNABB III |
CHIEF EXECUTIVE OFFICER |
Certification Pursuant to 18 U.S.C. Section 1350,
As Adopted Pursuant to
Section 906 of the Sarbanes-Oxley Act of 2002
Name of Issuer: Vanguard Institutional Index Funds
In connection with the Report on Form N-CSR of the above-named issuer that is accompanied by this certification, the undersigned hereby certifies, to his knowledge, that:
1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and
2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the issuer.
Date: August 12, 2009
/s/ THOMAS J. HIGGINS |
THOMAS J. HIGGINS |
CHIEF FINANCIAL OFFICER |