SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Form N-1A
REGISTRATION STATEMENT (NO. 33-34494) UNDER
THE SECURITIES ACT OF 1933
Pre-Effective Amendment No.
Post-Effective Amendment No. 16
and
REGISTRATION STATEMENT (811-6093) UNDER
THE INVESTMENT COMPANY ACT OF 1940
Amendment No. 17
VANGUARD INSTITUTIONAL INDEX FUND
(Exact Name of Registrant as Specified in Declaration of Trust)
Post Office Box 2600, Valley Forge, PA 19482
(Address of Principal Executive Office)
Registrant's Telephone Number (610) 669-1000
R.GREGORY BARTON, ESQUIRE
P.O. BOX 876
VALLEY FORGE, PA 19482
It is proposed that this filing become effective: on April 30, 1999
pursuant to paragraph (b)(1)(iii) of Rule 485.
Approximate Date of Proposed Public Offering As soon as practicable after
this Registration Statement becomes effective.
We have elected to register an indefinite number of shares pursuant to Rule
24f-2 under the Investment Company Act of 1940. We filed our Rule 24f-2 Notice
for the year ended December 31, 1998 on March 29, 1999.
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The Part A, Part B and Part C of the filing in Form N-1A for Vanguard
Institutional Index Fund are hereby incorporated by reference. Please refer to
the 485 (a)Post-Effective Amendment No. 15 which was filed with the Securities
and Exchange Commission on February 25, 1999, File Number 33-34494.
