VANGUARD INDEX TRUST
485APOS, 1999-02-25
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<PAGE>   1
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                                   FORM N-1A
                   REGISTRATION STATEMENT (NO. 2-56846) UNDER
                           THE SECURITIES ACT OF 1933
                          PRE-EFFECTIVE AMENDMENT NO.
   
                        POST-EFFECTIVE AMENDMENT NO. 53
    
                                      AND
 
              REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY
                                  ACT OF 1940
   
                                AMENDMENT NO. 55
    
                              VANGUARD INDEX TRUST
   
        (EXACT NAME OF REGISTRANT AS SPECIFIED IN DECLARATION OF TRUST)
    
 
                     P.O. 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 AMENDMENT BECOME EFFECTIVE
   
            on April 26, 1999 pursuant to paragraph (a) 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
REGULATION 24f-2 UNDER THE INVESTMENT COMPANY ACT OF 1940. WE FILED OUR RULE
24f-2 NOTICE FOR THE YEAR ENDED DECEMBER 31, 1998 ON      --     .
    
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>   2
 
                              VANGUARD INDEX TRUST
 
                             CROSS REFERENCE SHEET
 
   
<TABLE>
<CAPTION>
                             FORM N-1A
                            ITEM NUMBER                                      LOCATION IN PROSPECTUS
<C>           <S>                                                     <C>
    Item 1.   Front and Back Cover Pages...........................   Front and Back Cover Pages
    Item 2.   Risk/Return Summary: Investments, Risks, and
              Performance..........................................   Fund Profile
    Item 3.   Risk/Return Summary: Fee Table.......................   Fee Table
    Item 4.   Investment Objectives, Principal Investment
              Strategies, and Related Risks........................   A Word About Risk; Who Should Invest;
                                                                      Primary Investment Strategies
    Item 5.   Management's Discussion of Fund Performance..........   Herein incorporated by reference to
                                                                      Registrant's Annual Report to
                                                                      Shareholders dated December 31, 1998
                                                                      filed with the Securities & Exchange
                                                                      Commission's EDGAR system on --
    Item 6.   Management, Organization, and Capital
              Structure............................................   The Fund and Vanguard; Investment
                                                                      Adviser
    Item 7.   Shareholder Information..............................   Share Price; Dividends, Capital
                                                                      Gains, and Taxes; Investing with
                                                                      Vanguard
    Item 8.   Distribution Arrangements............................   Inside Front Cover Page
    Item 9.   Financial Highlights Information.....................   Financial Highlights
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                             FORM N-1A                                        LOCATION IN STATEMENT
                            ITEM NUMBER                                     OF ADDITIONAL INFORMATION
<C>           <S>                                                     <C>
   Item 10.   Cover Page and Table of Contents.....................   Cover Page; Table of Contents
   Item 11.   Fund History.........................................   Description of the Trust
   Item 12.   Description of the Fund and its Investments and
              Risks................................................   Description of the Trust; Investment
                                                                      Policies; Fundamental Investment
                                                                      Limitations
   Item 13.   Management of the Fund...............................   Management of the Trust
   Item 14.   Control Persons and Principal Holders of
              Securities...........................................   Management of the Trust
   Item 15.   Investment Advisory and Other Services...............   Investment Advisory Services
   Item 16.   Brokerage Allocation and Other Services..............   Portfolio Transactions
   Item 17.   Capital Stock and Other Securities...................   Description of the Trust
   Item 18.   Purchase, Redemption, and Pricing of Shares..........   Purchase of Shares; Redemption of
                                                                      Shares; Share Price
   Item 19.   Taxation of the Fund.................................   Description of the Trust
   Item 20.   Underwriters.........................................   Not Applicable
   Item 21.   Calculation of Performance Data......................   Yield and Total Return
   Item 22.   Financial Statements.................................   Financial Statements
</TABLE>
    
<PAGE>   3
   

VANGUARD U.S. STOCK INDEX FUNDS

Prospectus 
April 26, 1999


                                    CONTENTS

1     AN INTRODUCTION TO INDEX FUNDS

2     FUND PROFILES

      2     Vanguard Total Stock Market Index Fund

      4     Vanguard 500 Index Fund

      6     Vanguard Extended Market Index Fund

      8     Vanguard Mid-Cap Index Fund

      10    Vanguard Small-Cap Index Fund

      12    Vanguard Value Index Fund

      14    Vanguard Small-Cap Value Index Fund

      16    Vanguard Growth Index Fund

      18    Vanguard Small-Cap Growth Index Fund

20    MORE ON THE FUNDS

23    THE FUNDS AND VANGUARD

23    INVESTMENT ADVISER

24    YEAR 2000 CHALLENGE

24    DIVIDENDS, CAPITAL GAINS, AND TAXES

25    SHARE PRICE

26    FINANCIAL HIGHLIGHTS

30    INVESTING WITH VANGUARD

30    SERVICES AND ACCOUNT FEATURES

31    TYPES OF ACCOUNTS

31    BUYING SHARES

33    REDEEMING SHARES

36    TRANSFERRING REGISTRATION

37    FUND AND ACCOUNT UPDATES

GLOSSARY (inside back cover)


WHY READING THIS PROSPECTUS IS IMPORTANT

This prospectus explains the objective, risks, and strategies of each of the
Vanguard U.S. Stock Index Funds. To highlight terms and concepts important to
mutual fund investors, we have provided "Plain Talk(R)" explanations along the
way. Reading the prospectus will help you to decide which Funds, if any, are the
right investments for you. We suggest that you keep it for future reference.

IMPORTANT NOTE

Each of the Vanguard U.S. Stock Index Funds offers two separate classes of
shares: Investor and Institutional (except Vanguard 500 Index Fund, which offers
only Investor Shares). Investor Shares, which have an investment minimum of
$3,000 ($1,000 for IRAs), are offered by two separate prospectuses. This
prospectus is intended for individual investors and institutional clients. There
is also a prospectus for participants in employer-sponsored retirement plans,
which you can obtain by calling Vanguard at 1-800-523-1188. 

Institutional Shares have an investment minimum of $10 million and generally do
not require special employee benefit plan services. These Shares are offered by
another prospectus, which you can obtain by calling Vanguard's Institutional
Investor Group at 1-800-523-1036. 

Note that the Funds' separate share classes have different expenses; as a
result, their investment performance will vary.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.
<PAGE>   4
                                                                               1

 
      This prospectus provides information about the nine Vanguard U.S. Stock
Index Funds. After the introduction below, you'll find profiles that summarize
key features of each Fund. Following the profiles, there is important additional
information common to all of the Funds.


AN INTRODUCTION TO INDEX FUNDS

WHAT IS INDEXING?

An index is an unmanaged group of securities whose overall performance is used
as a standard to measure investment performance. An index (or "passively
managed") fund tries to match, as closely as possible, the performance of an
established target index. The fund does this by holding all, or a representative
sample, of the securities in the index.

      Index funds may seek to track indexes that hold a certain type of
stock--such as growth or value, small-cap or large-cap, or those from just one
industry--or they may seek to track indexes that consist of a broader range of
stocks--for example, the entire U.S. stock market.

      Index funds are not actively managed by investment advisers who buy and
sell securities based on research and analysis, in an attempt to outperform the
market as a whole. Rather, index funds simply mirror what the target index does,
for better or worse.

WHY INVEST IN INDEX FUNDS?

Index funds appeal to many investors for a number of reasons:

- -     Simplicity. Indexing is a straightforward market-matching strategy.

- -     Diversification. Indexes generally cover a wide variety of companies and
      industries.

- -     Relative performance predictability. An index fund is expected to closely
      parallel the performance of its target index.

- -     Low cost. Index funds do not have many of the expenses of an actively
      managed fund--such as research--and keep trading activity, and thus
      brokerage commissions, to a minimum.

- -     Low realization of capital gains. Because an index fund typically sells
      securities only to respond to redemption requests or to adjust the number
      of shares it holds to reflect a change in its target index, the fund's
      turnover rate--and thus its realization of taxable capital gains--is
      usually very low.

      KEEP IN MIND THAT AN INDEX FUND HAS OPERATING EXPENSES AND TRANSACTION
COSTS; A MARKET INDEX DOES NOT. THEREFORE, AN INDEX FUND--WHILE EXPECTED TO
TRACK ITS TARGET INDEX AS CLOSELY AS POSSIBLE--WILL TYPICALLY BE UNABLE TO MATCH
THE PERFORMANCE OF THE INDEX EXACTLY.

      For more information about index funds, see "Indexing Methods" under MORE
ON THE FUNDS.

                                PLAIN TALK ABOUT
                             THE COSTS OF INVESTING

Costs are an important consideration in choosing a mutual fund. That's because
you, as a shareholder, pay the costs of operating a fund, plus any transaction
costs associated with the fund's buying and selling of securities. These costs
can erode a substantial portion of the gross income or capital appreciation a
fund achieves. Even seemingly small differences in fund expenses can, over time,
have a dramatic effect on a fund's performance.
<PAGE>   5
2


FUND PROFILE--VANGUARD TOTAL STOCK MARKET INDEX FUND

The following profile summarizes key features of Vanguard Total Stock Market
Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of the overall stock market.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Wilshire 5000 Equity Index, which consists of all the U.S. common stocks
regularly traded on the New York and American Stock Exchanges and the Nasdaq
over-the-counter market.

PRIMARY RISK

THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
Stock markets tend to move in cycles, with periods of rising prices and periods
of falling prices.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year since
the Fund's inception. The table shows how the Fund's average annual returns for
one and five calendar years and since inception compare with those of the index
that the Fund seeks to track. Keep in mind that the Fund's past performance does
not indicate how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------








- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

      During the period shown in the bar chart, the highest return for a
calendar quarter was - % (quarter ended _____________ ) and the lowest return 
for a quarter was - - % (quarter ended _____________ ).


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                             1 YEAR   5 YEARS   SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                          <C>      <C>       <C>
Vanguard Total Stock Market Index Fund          - %      - %          - %
Wilshire 5000 Index                             -        -            -
- --------------------------------------------------------------------------------
* April 27, 1992.
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   6
                                                                               3


FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                         <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                   None
Transaction Fees on Purchases:                                              None
Sales Charge (Load) Imposed on Reinvested Dividends:                        None
Redemption Fees:                                                            None
Exchange Fees:                                                              None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                         - %
12b-1 Marketing Fees:                                                       None
Other Expenses:                                                              - %
   TOTAL ANNUAL FUND OPERATING EXPENSES:                                     - %
</TABLE>

      For accounts with current balances of less than $10,000, Vanguard will
deduct an account maintenance fee ($2.50 each quarter) from your quarterly
distribution of the Fund's dividends. If your distribution is less than the fee,
fractional shares will be automatically redeemed to make up the difference.

      The following example is intended to help you compare the cost of
investing in the Fund with the cost of investing in other mutual funds. It
illustrates the hypothetical expenses that you would incur over various periods
if you invest $10,000 in the Fund. This example assumes that the Fund provides a
return of 5% a year, and that operating expenses remain the same. The results
apply whether or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C>
      $  -              $  -                $  -                  $  -
- --------------------------------------------------------------------------------
</TABLE>

      THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December 

INVESTMENT ADVISER 

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

April 27, 1992

NET ASSETS AS OF DECEMBER 31, 1998

$ - billion

SUITABLE FOR IRAS

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

TotSt

VANGUARD FUND NUMBER

085

CUSIP NUMBER

922908306

TICKER SYMBOL

VTSMX
<PAGE>   7
4


FUND PROFILE--VANGUARD 500 INDEX FUND

The following profile summarizes key features of Vanguard 500 Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's 500 Composite Stock Price Index, which is dominated by
the stocks of large U.S. companies.

PRIMARY RISKS

- -     THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE
      WITHIN A WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN
      LONG PERIODS. Stock markets tend to move in cycles, with periods of rising
      prices and periods of falling prices.

- -     The Fund is also subject to investment style risk, which is the chance
      that returns from large-capitalization stocks will trail returns from
      other asset classes or the overall stock market. Large-capitalization
      stocks tend to go through cycles of doing better--or worse--than the stock
      market in general. These periods have, in the past, lasted for as long as
      several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year over
a ten-year period. The table shows how the Fund's average annual returns for
one, five, and ten calendar years compare with those of the index that the Fund
seeks to track. Keep in mind that the Fund's past performance does not indicate
how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------








- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

      During the period shown in the bar chart, the highest return for a
calendar quarter was - % (quarter ended _____________ ) and the lowest return
for a quarter was minus - % (quarter ended _____________ ).


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                                  1 YEAR    5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                                               <C>       <C>        <C>
Vanguard 500 Index Fund                             - %        - %        - %
S&P 500 Index                                       -          -          -
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   8
                                                                               5


FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                         <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                   None
Transaction Fees on Purchases:                                              None
Sales Charge (Load) Imposed on Reinvested Dividends:                        None
Redemption Fees:                                                            None
Exchange Fees:                                                              None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                         - %
12b-1 Marketing Fees:                                                       None
Other Expenses:                                                              - %
   TOTAL ANNUAL FUND OPERATING EXPENSES:                                     - %
</TABLE>

      For accounts with current balances of less than $10,000, Vanguard will
deduct an account maintenance fee ($2.50 each quarter) from your quarterly
distribution of the Fund's dividends. If your distribution is less than the fee,
fractional shares will be automatically redeemed to make up the difference.

      The following example is intended to help you compare the cost of
investing in the Fund with the cost of investing in other mutual funds. It
illustrates the hypothetical expenses that you would incur over various periods
if you invest $10,000 in the Fund. This example assumes that the Fund provides a
return of 5% a year, and that operating expenses remain the same. The results
apply whether or not you redeem your investment at the end of each period.

<TABLE>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C>
      $  -              $  -                $  -                   $  -
- --------------------------------------------------------------------------------
</TABLE>

      THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December 

INVESTMENT ADVISER

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

August 31, 1976

NET ASSETS AS OF DECEMBER 31, 1998

$ - billion

SUITABLE FOR IRAS

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

500

VANGUARD FUND NUMBER

040

CUSIP NUMBER

922908108

TICKER SYMBOL

VFINX
<PAGE>   9
6


FUND PROFILE--VANGUARD EXTENDED MARKET INDEX FUND

The following profile summarizes key features of Vanguard Extended Market Index
Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of mid- and small-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Wilshire 4500 Equity Index, a broadly diversified index of stocks of
medium-size and small U.S. companies. The Wilshire 4500 Index contains all of
the U.S. common stocks regularly traded on the New York and American Stock
Exchanges and the Nasdaq over-the-counter market, except those stocks included
in the S&P 500 Index.

PRIMARY RISKS

- -     THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE
      WITHIN A WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN
      LONG PERIODS. Stock markets tend to move in cycles, with periods of rising
      prices and periods of falling prices.

- -     The Fund is also subject to investment style risk, which is the chance
      that returns from mid- or small-capitalization stocks will trail returns
      from other asset classes or the overall stock market. Each type of stock
      tends to go through cycles of doing better--or worse--than the stock
      market in general. These periods have, in the past, lasted for as long as
      several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year over
a ten-year period. The table shows how the Fund's average annual returns for
one, five, and ten calendar years compare with those of the index that the Fund
seeks to track. Keep in mind that the Fund's past performance does not indicate
how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------








- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000, or the transaction fee of 0.25%
on purchases.
- --------------------------------------------------------------------------------


      During the period shown in the bar chart, the highest return for a
calendar quarter was - % (quarter ended _____________ ) and the lowest return
for a quarter was minus - % (quarter ended _____________ ).


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                                   1 YEAR    5 YEARS   10 YEARS
- --------------------------------------------------------------------------------
<S>                                                <C>       <C>       <C>
Vanguard Extended Market Index Fund                  - %        - %       - %
Wilshire 4500 Index                                  -          -         -
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   10
                                                                               7


FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                             <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                  0.25%*
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                              - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                   - %
   TOTAL ANNUAL FUND OPERATING EXPENSES:                                          - %
</TABLE>

* The transaction fee is deducted from all purchases (including exchanges from
  other Vanguard funds), but not from reinvested dividends and capital gains.

      For accounts with current balances of less than $10,000, Vanguard will
deduct an account maintenance fee ($10 each December) from your annual
distribution of the Fund's dividends. If your distribution is less than the fee,
fractional shares will automatically be redeemed to make up the difference.

      The following example is intended to help you compare the cost of
investing in the Fund with the cost of investing in other mutual funds. It
illustrates the hypothetical expenses that you would incur over various periods
if you invest $10,000 in the Fund. This example assumes that the Fund provides a
return of 5% a year, and that operating expenses remain the same. The results
apply whether or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C> 
      $  -              $  -                $  -                   $  -
- --------------------------------------------------------------------------------
</TABLE>

      THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Paid annually in December

INVESTMENT ADVISER

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

December 21, 1987

NET ASSETS AS OF DECEMBER 31, 1998

$ - billion

SUITABLE FOR IRAS

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

Extnd

VANGUARD FUND NUMBER

098

CUSIP NUMBER

922908207

TICKER SYMBOL

VEXMX
<PAGE>   11
8


FUND PROFILE--VANGUARD MID-CAP INDEX FUND

The following profile summarizes key features of Vanguard Mid-Cap Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of mid-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's MidCap 400 Index, which is made up of a group of
medium-size U.S. companies.

PRIMARY RISKS

- -     THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE
      WITHIN A WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN
      LONG PERIODS. Stock markets tend to move in cycles, with periods of rising
      prices and periods of falling prices.

- -     The Fund is also subject to investment style risk, which is the chance
      that returns from mid-capitalization stocks will trail returns from other
      asset classes or the overall stock market. Mid-capitalization stocks tend
      to go through cycles of doing better--or worse--than the stock market in
      general. These periods have, in the past, lasted for as long as several
      years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                             <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                  0.25%*
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

* The transaction fee is deducted from all purchases (including exchanges from
  other Vanguard funds), but not from reinvested dividends and capital gains.

Annual Fund Operating Expenses (expenses deducted from the Fund's assets)
Management Expenses:                                                              - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                   - %
   Total Annual Fund Operating Expenses:                                          - %
</TABLE>

      For accounts with current balances of less than $10,000, Vanguard will
deduct an account maintenance fee ($10 each December) from your annual
distribution of the Fund's dividends. If your distribution is less than the fee,
fractional shares will be automatically redeemed to make up the difference.
<PAGE>   12
                                                                               9


      The following example is intended to help you compare the cost of
investing in the Fund with the cost of investing in other mutual funds. It
illustrates the hypothetical expenses that you would incur over various periods
if you invest $10,000 in the Fund. This example assumes that the Fund provides a
return of 5% a year, and that operating expenses remain the same. The results
apply whether or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C> 
      $  -              $  -                $  -                   $  -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Paid annually in December

INVESTMENT ADVISER

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998

$ - billion

SUITABLE FOR IRAS

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

MidCp

VANGUARD FUND NUMBER

859

CUSIP NUMBER

922908843

TICKER SYMBOL

VIMSX
<PAGE>   13
10


FUND PROFILE--VANGUARD SMALL-CAP INDEX FUND

The following profile summarizes key features of Vanguard Small-Cap Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Russell 2000 Small Stock Index, which is made up of the stocks of smaller
U.S. companies. The Russell 2000 Index is comprised of the 2,000 smallest
companies out of the 3,000 largest U.S. companies.

PRIMARY RISKS

- -     THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE
      WITHIN A WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN
      LONG PERIODS. Stock markets tend to move in cycles, with periods of rising
      prices and periods of falling prices.

- -     The Fund is also subject to investment style risk, which is the chance
      that returns from small-capitalization stocks will trail returns from
      other asset classes or the overall stock market. Small-capitalization
      stocks tend to go through cycles of doing better--or worse--than the stock
      market in general. These periods have, in the past, lasted for as long as
      several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year over
a ten-year period. The table shows how the Fund's average annual returns for
one, five, and ten calendar years compare with those of the index that the Fund
seeks to track. Keep in mind that the Fund's past performance does not indicate
how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------








- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000, or the transaction fee of 0.50%
on purchases.
- --------------------------------------------------------------------------------

      During the period shown in the bar chart, the highest return for a
calendar quarter was -% (quarter ended _____________ ) and the lowest return
for a quarter was -% (quarter ended _____________ ).


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                                   1 YEAR    5 YEARS   10 YEARS
- --------------------------------------------------------------------------------
<S>                                                <C>       <C>       <C>
Vanguard Small-Cap Index Fund                         -%        -%       -%
Russell 2000 Index                                    -         -         -
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   14
                                                                              11


FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                             <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                  0.50%*
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                              - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                   - %
   TOTAL ANNUAL FUND OPERATING EXPENSES:                                          - %
</TABLE>

*The transaction fee is deducted from all purchases (including exchanges from
 other Vanguard funds), but not from reinvested dividends and capital gains.

      For accounts with current balances of less than $10,000, Vanguard will
deduct an account maintenance fee ($10 each December) from your annual
distribution of the Fund's dividends. If your distribution is less than the fee,
fractional shares will be automatically redeemed to make up the difference.

      The following example is intended to help you compare the cost of
investing in the Fund with the cost of investing in other mutual funds. It
illustrates the hypothetical expenses that you would incur over various periods
if you invest $10,000 in the Fund. This example assumes that the Fund provides a
return of 5% a year, and that operating expenses remain the same. The results
apply whether or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C> 
      $ -               $ -                 $ -                   $ -
- --------------------------------------------------------------------------------
</TABLE>

      THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Paid annually in December

INVESTMENT ADVISER

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

October 3, 1960

NET ASSETS AS OF DECEMBER 31, 1998

$- billion

SUITABLE FOR IRAS

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

SmCap

VANGUARD FUND NUMBER

048

CUSIP NUMBER

922908702

TICKER SYMBOL

NAESX
<PAGE>   15
12


FUND PROFILE--VANGUARD VALUE INDEX FUND

The following profile summarizes key features of Vanguard Value Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization value stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's/BARRA Value Index, which includes those stocks of the
S&P 500 Index with lower than average price/book ratios.

PRIMARY RISKS

- -     THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE
      WITHIN A WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN
      LONG PERIODS. Stock markets tend to move in cycles, with periods of rising
      prices and periods of falling prices.

- -     The Fund is also subject to investment style risk, which is the chance
      that returns from value stocks will trail returns from other asset classes
      or the overall stock market. Value stocks tend to go through cycles of
      doing better--or worse--than the stock market in general. These periods
      have, in the past, lasted for as long as several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year since
the Fund's inception. The table shows how the Fund's average annual returns for
one and five calendar years and since inception compare with those of the index
that the Fund seeks to track. Keep in mind that the Fund's past performance does
not indicate how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------








- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

      During the period shown in the bar chart, the highest return for a
calendar quarter was -% (quarter ended _____________ ) and the lowest return
for a quarter was -% (quarter ended _____________ ).

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                          1 YEAR    5 YEARS    SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                       <C>       <C>        <C>
Vanguard Value Index Fund                   -%         -%            -%
S&P/BARRA Value Index                       -          -             -
- --------------------------------------------------------------------------------
*November 2, 1992.
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   16
                                                                              13


FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                         <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                   None
Transaction Fees on Purchases:                                              None
Sales Charge (Load) Imposed on Reinvested Dividends:                        None
Redemption Fees:                                                            None
Exchange Fees:                                                              None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                         - %
12b-1 Marketing Fees:                                                       None
Other Expenses:                                                              - %
   TOTAL ANNUAL FUND OPERATING EXPENSES:                                     - %
</TABLE>

      For accounts with current balances of less than $10,000, Vanguard will
deduct an account maintenance fee ($2.50 each quarter) from your quarterly
distribution of the Fund's dividends. If your distribution is less than the fee,
fractional shares will be automatically redeemed to make up the difference.

      The following example is intended to help you compare the cost of
investing in the Fund with the cost of investing in other mutual funds. It
illustrates the hypothetical expenses that you would incur over various periods
if you invest $10,000 in the Fund. This example assumes that the Fund provides a
return of 5% a year, and that operating expenses remain the same. The results
apply whether or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C> 
      $  -              $  -                $  -                   $  -
- --------------------------------------------------------------------------------
</TABLE>

      THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

November 2, 1992

NET ASSETS AS OF DECEMBER 31, 1998

$ - billion

SUITABLE FOR IRAS

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

Value

VANGUARD FUND NUMBER

006

CUSIP NUMBER

922908405

TICKER SYMBOL

VIVAX
<PAGE>   17
14


FUND PROFILE--VANGUARD SMALL-CAP VALUE INDEX FUND

The following profile summarizes key features of Vanguard Small-Cap Value Index
Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization value stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's SmallCap 600/BARRA Value Index, which includes those
stocks of the S&P SmallCap 600 Index with lower than average price/book ratios.

PRIMARY RISKS

- -     THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE
      WITHIN A WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN
      LONG PERIODS. Stock markets tend to move in cycles, with periods of rising
      prices and periods of falling prices.

- -     The Fund is also subject to investment style risk, which is the chance
      that returns from small-capitalization value stocks will trail returns
      from other asset classes or the overall stock market. Small-capitalization
      value stocks tend to go through cycles of doing better--or worse--than the
      stock market in general. These periods have, in the past, lasted for as
      long as several years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                             <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                  1.00%*
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                              - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                   - %
   TOTAL ANNUAL FUND OPERATING EXPENSES:                                          - %
</TABLE>

* The transaction fee is deducted from all purchases (including exchanges from
  other Vanguard funds), but not from reinvested dividends and capital gains.

      For accounts with current balances of less than $10,000, Vanguard will
deduct an account maintenance fee ($10 each December) from your annual
distribution of the Fund's dividends. If your distribution is less than the fee,
fractional shares will be automatically redeemed to make up the difference.
<PAGE>   18
                                                                              15


      The following example is intended to help you compare the cost of
investing in the Fund with the cost of investing in other mutual funds. It
illustrates the hypothetical expenses that you would incur over various periods
if you invest $10,000 in the Fund. This example assumes that the Fund provides a
return of 5% a year, and that operating expenses remain the same. The results
apply whether or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C> 
      $  -              $  -                $  -                   $  -
- --------------------------------------------------------------------------------
</TABLE>

      THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Paid annually in December

INVESTMENT ADVISER

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998

$ - billion

SUITABLE FOR IRAS

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

SmVal

VANGUARD FUND NUMBER

860

CUSIP NUMBER

922908793

TICKER SYMBOL

VISVX
<PAGE>   19
16


FUND PROFILE--VANGUARD GROWTH INDEX FUND

The following profile summarizes key features of Vanguard Growth Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization growth stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's/BARRA Growth Index, which includes those stocks of the
S&P 500 Index with higher than average price/book ratios.

PRIMARY RISKS

- -     THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE
      WITHIN A WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN
      LONG PERIODS. Stock markets tend to move in cycles, with periods of rising
      prices and periods of falling prices.

- -     The Fund is also subject to investment style risk, which is the chance
      that returns from growth stocks will trail returns from other asset
      classes or the overall stock market. Growth stocks tend to go through
      cycles of doing better--or worse--than the stock market in general. These
      periods have, in the past, lasted for as long as several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year since
the Fund's inception. The table shows how the Fund's average annual returns for
one and five calendar years and since inception compare with those of the index
that the Fund seeks to track. Keep in mind that the Fund's past performance does
not indicate how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------








- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

      During the period shown in the bar chart, the highest return for a
calendar quarter was - % (quarter ended _____________ ) and the lowest return
for a quarter was minus - % (quarter ended _____________ ).

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                           1 YEAR    5 YEARS    SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                        <C>       <C>        <C>
Vanguard Growth Index Fund                    - %       - %           - %
S&P/BARRA Growth Index                        -         -             -
- --------------------------------------------------------------------------------
* November 2, 1992.
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   20
                                                                              17


FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                         <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                   None
Transaction Fees on Purchases:                                              None
Sales Charge (Load) Imposed on Reinvested Dividends:                        None
Redemption Fees:                                                            None
Exchange Fees:                                                              None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                         - %
12b-1 Marketing Fees:                                                       None
Other Expenses:                                                              - %
   TOTAL ANNUAL FUND OPERATING EXPENSES:                                     - %
</TABLE>

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($2.50 each quarter) from your annual distribution of
the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C> 
      $  -              $  -                $  -                   $  -
- --------------------------------------------------------------------------------
</TABLE>

      THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

November 2, 1992

NET ASSETS AS OF DECEMBER 31, 1998

$ - billion

SUITABLE FOR IRAS

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

Growth

VANGUARD FUND NUMBER

009

CUSIP NUMBER

922908504

TICKER SYMBOL

VIGRX
<PAGE>   21
18


FUND PROFILE--VANGUARD SMALL-CAP GROWTH INDEX FUND

The following profile summarizes key features of Vanguard Small-Cap Growth Index
Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization growth stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's SmallCap 600/BARRA Growth Index, which includes those
stocks of the S&P SmallCap 600 Index with higher than average price/book ratios.

PRIMARY RISKS

- -     THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE
      WITHIN A WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN
      LONG PERIODS. Stock markets tend to move in cycles, with periods of rising
      prices and periods of falling prices.

- -     The Fund is also subject to investment style risk, which is the chance
      that returns from small-capitalization growth stocks will trail returns
      from other asset classes or the overall stock market. Small-capitalization
      growth stocks tend to go through cycles of doing better--or worse--than
      the stock market in general. These periods have, in the past, lasted for
      as long as several years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                             <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                  1.00%*
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                              - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                   - %
   TOTAL ANNUAL FUND OPERATING EXPENSES:                                          - %
</TABLE>

* The transaction fee is deducted from all purchases (including exchanges from
  other Vanguard funds), but not from reinvested dividends and capital gains.

      For accounts with current balances of less than $10,000, Vanguard will
deduct an account maintenance fee ($10 each December) from your annual
distribution of the Fund's dividends. If your distribution is less than the fee,
fractional shares will be automatically redeemed to make up the difference.
<PAGE>   22
                                                                              19


      The following example is intended to help you compare the cost of
investing in the Fund with the cost of investing in other mutual funds. It
illustrates the hypothetical expenses that you would incur over various periods
if you invest $10,000 in the Fund. This example assumes that the Fund provides a
return of 5% a year, and that operating expenses remain the same. The results
apply whether or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
     1 YEAR            3 YEARS             5 YEARS               10 YEARS
- --------------------------------------------------------------------------------
<S>                    <C>                 <C>                   <C> 
      $  -              $  -                $  -                   $  -
- --------------------------------------------------------------------------------
</TABLE>

      THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS

Paid annually in December

INVESTMENT ADVISER

Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE

May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998

$ - billion

SUITABLE FOR IRAs

Yes

MINIMUM INITIAL INVESTMENT

$3,000; $1,000 for IRAs and custodial accounts for minors

NEWSPAPER ABBREVIATION

SmGth

VANGUARD FUND NUMBER

861

CUSIP NUMBER

922908827

TICKER SYMBOL

VISGX
<PAGE>   23
20


MORE ON THE FUNDS

The following sections discuss other important features of Vanguard U.S. Stock
Index Funds.

INDEXING METHODS

In seeking to track a particular index, a fund generally uses one of two methods
to select stocks.

      Some index funds hold each stock found in their target indexes in about
the same proportions as represented in the indexes themselves. This is called a
"replication" method. For example, if 5% of the S&P 500 Index were made up of
the stock of a specific company, a fund tracking that index (such as Vanguard
500 Index Fund) would invest about 5% of its assets in that company. The 500,
Mid-Cap, Value, Small-Cap Value, Growth, and Small-Cap Growth Index Funds employ
this method of indexing.

      Because it would be very expensive to buy and sell all of the stocks held
in certain indexes (the Wilshire 5000 Index, for example, includes more than
7,200 stocks), funds tracking these larger indexes use a "sampling" technique.
Using a sophisticated computer program, these funds select a representative
sample of stocks from their target index that will resemble the full index in
terms of industry weightings, market capitalization, price/earnings ratio,
dividend yield, and other characteristics. For instance, if 10% of the Wilshire
5000 Index were made up of utility stocks, the Total Stock Market Index Fund
would invest about 10% of its assets in some--but not all--of those utility
stocks. The particular utility stocks selected by the Fund, as a group, would
have investment characteristics similar to those of the utility stocks in the
Index. The Total Stock Market, Extended Market, and Small-Cap Index Funds employ
this method of indexing.


      The following table shows the number of stocks held by each of the Funds
as of December 31, 1998.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
FUND                   NUMBER OF STOCKS HELD    NUMBER OF STOCKS IN TARGET INDEX
- --------------------------------------------------------------------------------
<S>                    <C>                      <C>
Total Stock Market
500
Extended Market
Mid-Cap
Small-Cap
Value
Small-Cap Value
Growth
Small-Cap Growth
- --------------------------------------------------------------------------------
</TABLE>

                                PLAIN TALK ABOUT
                          GROWTH FUNDS AND VALUE FUNDS

Growth investing and value investing are two styles employed by stock fund
managers. Growth funds generally focus on companies believed to have
above-average potential for growth in revenue and earnings. Reflecting the
market's high expectations for superior growth, the prices of such stocks are
typically above-average in relation to such measures as revenue, earnings, book
value, and dividends. Value funds generally emphasize companies from which the
market does not expect strong growth. The prices of value stocks typically are
below-average in comparison to such factors as earnings and book value, and
these stocks typically pay above-average dividend yields. Growth and value
stocks have, in the past, produced similar long-term returns, though each
category has periods when it outperforms the other. In general, growth funds
appeal to investors who will accept more volatility in hopes of a greater
increase in share price. Growth funds also may appeal to investors with taxable
accounts who want a higher proportion of returns to come as capital gains (which
may be taxed at lower rates than dividend income). Value funds, by contrast, are
appropriate for investors who want some dividend income and the potential for
capital gains, but are less tolerant of share-price fluctuations.
<PAGE>   24
                                                                              21


                                PLAIN TALK ABOUT
                    LARGE-CAP, MID-CAP, AND SMALL-CAP STOCKS

Stocks of publicly traded companies--and mutual funds that hold these
stocks--can be classified by the companies' market value, or capitalization.
Generally, Vanguard defines large-capitalization (large-cap) funds as those
holding stocks of companies whose outstanding shares have a market value
exceeding $10 billion. Mid-cap funds hold stocks of companies with a market
value between $1 billion and $10 billion. Small-cap funds typically hold stocks
of companies with a market value of less than $1 billion.


ADDITIONAL RISK INFORMATION

[FLAG] EACH FUND IS SUBJECT TO MARKET RISK, WHICH IS THE POSSIBILITY THAT STOCK
       PRICES OVERALL WILL DECLINE OVER SHORT OR EVEN LONG PERIODS. STOCK 
       MARKETS TEND TO MOVE IN CYCLES, WITH PERIODS OF RISING STOCK PRICES AND 
       PERIODS OF FALLING STOCK PRICES.

      To illustrate the volatility of stock prices, the following table shows
the best, worst, and average total returns for the U.S. stock market over
various periods as measured by the S&P 500 Index, which--in addition to being
the target index for Vanguard 500 Index Fund--is a widely used barometer of
stock market activity. (Total returns consist of dividend income plus change in
market price.) Note that the returns shown do not include the costs of buying
and selling stocks or other expenses that a real-world investment portfolio
would incur. Note, also, that the gap between best and worst tends to narrow
over the long term.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                      U.S. STOCK MARKET RETURNS (1926-1998)
- --------------------------------------------------------------------------------
                                1 YEAR      5 YEARS     10 YEARS      20 YEARS
- --------------------------------------------------------------------------------
<S>                             <C>         <C>         <C>           <C>  
Best                             54.2%        24.1%       19.9%         17.7%
Worst                           -43.1        -12.4        -0.8           3.1
Average                          13.1         10.7        11.0          11.0
- --------------------------------------------------------------------------------
</TABLE>

      The table covers all of the 1-, 5-, 10-, and 20-year periods from 1926
through 1998. You can see, for example, that while the average return on stocks
for all of the 5-year periods was 10.7%, returns for individual 5-year periods
ranged from a -12.4% average (from 1928 through 1932) to 24.1% (from 1994
through 1998). These average returns reflect past performance on common stocks;
you should not regard them as an indication of future returns from either the
stock market as a whole or any Fund in particular.

      Keep in mind that the S&P 500 Index tracks mainly large-capitalization
stocks. Historically, the mid- and small-cap stocks of the Wilshire 4500, S&P
MidCap 400, and Russell 2000 Indexes (the target indexes for the Extended
Market, Mid-Cap, and Small-Cap Index Funds, respectively) have been more
volatile than--and at times have performed quite differently from--the large-cap
stocks of the S&P 500 Index.

      Even indexes that are subsets of the S&P 500 Index--such as the S&P/BARRA
Value Index and the S&P/BARRA Growth Index (the target indexes for the Value and
Growth Index Funds)--will not perform in the same way as the broader S&P 500
Index. Historically, stocks of the S&P/BARRA Value Index have been less volatile
than the stocks found in the broader S&P 500 Index; stocks of the S&P/BARRA
Growth Index, on the other hand, have displayed somewhat greater short-term
volatility than the S&P 500 Index's stocks. Historical performance aside,
however, both value and growth stocks have the potential at times to be more
volatile than the broader market.

[FLAG] THE FUNDS ARE ALSO SUBJECT, IN VARYING DEGREES, TO INVESTMENT STYLE RISK,
       WHICH IS THE POSSIBILITY THAT RETURNS FROM A SPECIFIC TYPE OF STOCK (FOR
       INSTANCE, SMALL-CAP OR VALUE) WILL TRAIL RETURNS FROM OTHER ASSET CLASSES
       OR THE OVERALL STOCK MARKET. EACH TYPE OF STOCK TENDS TO GO THROUGH 
       CYCLES OF DOING BETTER--OR WORSE--THAN COMMON STOCKS IN GENERAL. THESE 
       PERIODS HAVE, IN THE PAST, LASTED FOR AS LONG AS SEVERAL YEARS.

TRANSACTION FEES AND ACCOUNT MAINTENANCE

Some of Vanguard's index funds charge a transaction fee on purchases of fund
shares to offset the higher costs of trading certain securities, particularly
small-company stocks. The transaction fee ensures that these higher costs are
<PAGE>   25
22


borne by the investors making the transactions--and not by shareholders already
in the fund. Without transaction fees, an index fund would have trouble tracking
its target index.

      In addition, most of Vanguard's index funds charge an account maintenance
fee on accounts under $10,000 to divide the costs of maintaining accounts
equitably among shareholders.

      At Vanguard, fees are paid directly into the fund itself (unlike the sales
charge or load imposed by many fund companies, which ends up in the pocket of
the sponsor, adviser, or sales representative).

COSTS AND MARKET-TIMING

Some investors try to profit from a strategy called market-timing--switching
money into investments when they expect prices to rise, and taking money out
when they expect prices to fall. As money is shifted in and out, a fund incurs
expenses for buying and selling securities. These costs are borne by all fund
shareholders, including the long-term investors who do not generate the costs.
Therefore, the Funds have adopted the following policies, among others, designed
to discourage short-term trading:

- -     Each Fund reserves the right to reject any purchase request--including
      exchanges from other Vanguard funds--that it regards as disruptive to the
      efficient management of the Fund. This could be because of the timing of
      the investment or because of a history of excessive trading by the
      investor.

- -     Five of the Funds (Extended Market, Mid-Cap, Small-Cap, Small-Cap Value,
      and Small-Cap Growth) charge a transaction fee on purchases.

- -     There is a limit on the number of times you can exchange into and out of a
      Fund (see "Redeeming Shares" in the INVESTING WITH VANGUARD section).

- -     Telephone and online exchanges are not permitted for non-IRA accounts.

      THE VANGUARD FUNDS DO NOT PERMIT MARKET-TIMING. DO NOT INVEST IN THESE
FUNDS IF YOU ARE A MARKET-TIMER.

                                PLAIN TALK ABOUT
                                  TURNOVER RATE

Before investing in a mutual fund, you should review its turnover rate. This
gives an indication of how transaction costs could affect the fund's future
returns. In general, the greater the volume of buying and selling by the fund,
the greater the impact that brokerage commissions and other transaction costs
will have on its return. Also, funds with high turnover rates may be more likely
to generate capital gains that must be distributed to shareholders as income
subject to taxes. The average turnover rate for passively managed domestic
equity index funds investing in common stocks is roughly -%; for all domestic
stock funds, the average turnover rate is approximately -%, according to
Morningstar, Inc.

TURNOVER RATE

Although each Fund seeks to invest for the long term, the Funds retain the right
to sell securities regardless of how long the securities have been held.
Generally, a passively managed fund sells securities only to respond to
redemption requests or to adjust the number of shares held to reflect a change
in the fund's target index. Because of this, the turnover rate for the Funds has
been extremely low, with averages over the past five years (or since inception)
ranging from 2% for the Total Stock Market Index Fund to 29% for the Small-Cap
Index Fund. (A turnover rate of 100% would occur, for example, if a Fund sold
and replaced securities valued at 100% of its net assets within a one-year
period.) The turnover rate of each Fund for each of the last five years (or the
life of the Fund, if shorter) is shown in the FINANCIAL HIGHLIGHTS section of
this prospectus.

INVESTMENT POLICIES

Each Fund reserves the right to substitute a different index for the index it
currently tracks if the current index is discontinued or for any other reason
determined in good faith by the Fund's Board of Trustees. In every such
instance, the substitute index will measure the same general market (large-,
mid-, or small-cap, growth, or value) as the current index.

      Each Fund may invest in foreign securities to the extent necessary to
carry out its investment strategy of holding all, or a representative sample, of
the stocks that comprise the index it tracks. It is not expected that any Fund
will invest more than 5% of its assets in foreign securities.
<PAGE>   26
                                                                              23


      Although index funds, by their nature, tend to be tax-efficient investment
vehicles, the Funds generally are managed without regard to tax ramifications.

      To track their target indexes as closely as possible, the Funds attempt to
remain fully invested in stocks. To help stay fully invested, and to reduce
transaction costs, the Funds may invest, to a limited extent, in stock futures
and options contracts, warrants, convertible securities, and swap agreements,
which are types of derivatives.

      Losses (or gains) involving futures can sometimes be substantial--in part
because a relatively small price movement in a futures may result in an
immediate and substantial loss (or gain) for a fund. Similar risks exist for
warrants (securities that permit their owners to purchase a specific number of
stock shares at a predetermined price), convertible securities (securities that
may be exchanged for another asset), and swap agreements (contracts in which
each party agrees to make payments to the other based on the return of a
specified index or asset).

      For this reason, the Funds will not use futures, options, warrants,
convertible securities, or swap agreements for speculative purposes or as
leveraged investments that magnify the gains or losses of an investment. The
value of all futures contracts in which any Fund acquires an interest cannot
exceed 20% of that Fund's total assets.

      The reasons for which a Fund will invest in futures and options are:

- -     To keep cash on hand to meet shareholder redemptions or other needs while
      simulating full investment in stocks.

- -     To reduce the Fund's transaction costs or add value when these instruments
      are favorably priced.


                                PLAIN TALK ABOUT
                      VANGUARD'S UNIQUE CORPORATE STRUCTURE

The Vanguard Group is truly a MUTUAL mutual fund company. It is owned jointly by
the funds it oversees and thus indirectly by the shareholders in those funds.
Most other mutual funds are operated by for-profit management companies that may
be owned by one person, by a group of individuals, or by investors who own the
management company's stock. By contrast, Vanguard provides its services on an
"at-cost" basis, and the funds' expense ratios reflect only these costs. No
separate management company reaps profits or absorbs losses from operating the
funds.


THE FUNDS AND VANGUARD

The Funds are members of The Vanguard Group, a family of more than 35 investment
companies with more than 100 distinct investment portfolios and holding assets
worth more than $ - billion. All of the funds share in the expenses associated
with business operations, such as personnel, office space, equipment, and
advertising.

      Vanguard also provides marketing services to the funds. Although
shareholders do not pay sales commissions or 12b-1 distribution fees, each fund
pays its allocated share of The Vanguard Group's marketing costs.


INVESTMENT ADVISER

Vanguard Core Management Group (the "Group"), P.O. Box 2600, Valley Forge, PA
19482, provides advisory services on an at-cost basis to the Vanguard U.S. Stock
Index Funds. For the fiscal year ended December 31, 1998, the Funds paid
advisory fees at an effective annual rate (applied to the average daily net
assets of each Fund) of - % for the Total Stock Market Index Fund; - % for the
500 Index Fund; - % for the Extended Market Index Fund; - % for the Small-Cap
Index Fund; - % for the Value Index Fund; and - % for the Growth Index Fund. As
of the date of this prospectus, the Mid-Cap, Small-Cap Value, and Small-Cap
Growth Index Funds had not operated for a full fiscal year; if they had, it is
estimated that they would have paid advisory fees (applied to average daily net
assets) of - %, - %, and - %, respectively.

      The Funds have authorized the Group to choose brokers or dealers to handle
the purchase and sale of securities for the Funds, and to get the best available
price and most favorable execution from these brokers with respect to all
transactions. The Funds may direct the Group to use a particular broker for
certain transactions in exchange for commission rebates or research services
provided to the Funds.
<PAGE>   27
24


                                PLAIN TALK ABOUT
                               THE FUNDS' ADVISER

Vanguard Core Management Group provides investment advisory services to many
Vanguard funds. As of December 31, 1998, the Group managed more than $___
billion in total assets. The individual responsible for overseeing each Fund's
investments is:

      GEORGE U. SAUTER, Managing Director of Vanguard; has worked in investment
management since 1985; has managed portfolio investments since 19__; with
Vanguard since 1987; A.B., Dartmouth College; M.B.A., University of Chicago.


YEAR 2000 CHALLENGE

The common practice in computer programming of using just two digits to identify
a year has resulted in the Year 2000 challenge throughout the information
technology industry. If unchanged, many computer applications and systems could
misinterpret dates occurring after December 31, 1999, leading to errors or
failure. Such failure could adversely affect a fund's operations, including
pricing, securities trading, and the servicing of shareholder accounts.

      The Vanguard Group is dedicated to providing uninterrupted, high-quality
performance from our computer systems before, during, and after 2000. In July
1998, we completed the renovation and initial testing of our internal systems.
Vanguard is diligently working with external partners, suppliers, and vendors,
including fund managers and other service providers, to assure that the systems
with which we interact remain operational at all times.

      In addition to taking every reasonable step to secure our internal systems
and external relationships, Vanguard is further developing contingency plans
intended to assure that unexpected systems failures will not adversely affect
the Funds' operations. Vanguard intends to monitor these processes through the
rollover of 1999 into 2000 and to quickly implement alternate solutions if
necessary.

      However, despite Vanguard's efforts and contingency plans, noncompliant
computer systems could have a material adverse effect on a Fund's business,
operations, or financial condition. Additionally, a Fund's performance could be
hurt if a computer-system failure at a company or governmental unit affects the
price of securities the Fund owns.

                                PLAIN TALK ABOUT
                                  DISTRIBUTIONS

As a shareholder, you are entitled to your share of the fund's income from
interest and dividends, and gains from the sale of investments. You receive such
earnings as either an income dividend or a capital gains distribution. Income
dividends come from both the dividends that the fund earns from its holdings and
the interest it receives from its money market and bond investments. Capital
gains are realized whenever the fund sells securities for higher prices than it
paid for them. The capital gains are either short-term or long-term depending on
whether the fund held the securities for less than or more than one year.


DIVIDENDS, CAPITAL GAINS, AND TAXES

The Funds distribute to shareholders virtually all of their net income (interest
and dividends less expenses) as well as any capital gains realized from the sale
of their holdings. Income distributions for the Total Stock Market, 500, Value,
and Growth Index Funds generally occur in March, June, September, and December;
income distributions for the Extended Market, Mid-Cap, Small-Cap, Small-Cap
Value, and Small-Cap Growth Index Funds generally occur in December. Capital
gains distributions for all nine Funds generally occur in December. In addition,
the Funds may occasionally be required to make supplemental dividend or capital
gains distributions at some other time during the year.

      You can receive distributions of income or capital gains in cash, or you
can have them automatically invested in more shares of a Fund. In either case,
these distributions are taxable to you. It is important to note that
distributions of dividends and capital gains that are declared in December--if
paid to you by the end of January--are taxed as if they had been paid to you in
December.
<PAGE>   28
                                                                              25


      Vanguard will send you a statement each year showing the tax status of all
your distributions. If you have chosen to receive dividend and/or capital gains
distributions in cash, and the postal or other delivery service is unable to
deliver checks to your address of record, we will change the distribution option
so that all dividends and other distributions are automatically invested in
additional shares. We will not pay interest on uncashed distribution checks. 

- -     The dividends and short-term capital gains that you receive are considered
      ordinary income for tax purposes.

- -     Any distributions of net long-term capital gains by a Fund are taxable to
      you as long-term capital gains, no matter how long you've owned shares in
      the Fund.

- -     Although the Funds do not seek to realize any particular amount of capital
      gains during a year, such gains are realized from time to time as
      by-products of their ordinary investment activities. Consequently,
      distributions may vary considerably from year to year.

- -     If you sell or exchange shares, any gain or loss you have is a taxable
      event. This means that you may have a capital gain to report as income, or
      a capital loss to report as a deduction, when you complete your federal
      income tax return.

- -     Distributions of dividends or capital gains, and capital gains or losses
      from your sale or exchange of Fund shares, may be subject to state and
      local income taxes as well.

      The tax information in this prospectus is provided as general information
and will not apply to you if you are investing through a tax-deferred account
such as an IRA or a qualified employee benefit plan. (Non-U.S. investors may be
subject to U.S. withholding and estate tax.) You should consult your tax adviser
about the tax consequences of an investment in one or more of the Funds.

      IMPORTANT NOTE: By law, each Fund must withhold 31% of your taxable
distributions and any redemption proceeds if you do not provide your correct
taxpayer identification number, or certify that it is correct, or if the IRS
instructs the Fund to do so.

                                PLAIN TALK ABOUT
                               "BUYING A DIVIDEND"

Unless you are investing through a tax-deferred retirement account (such as an
IRA), it is not to your advantage to buy shares of a fund shortly before it
makes a distribution, because doing so can cost you money in taxes. This is
known as "buying a dividend." For example: on December 15, you invest $5,000,
buying 250 shares for $20 each. If the fund pays a distribution of $1 per share
on December 16, its share price would drop to $19 (not counting market change).
You still have only $5,000 (250 shares x $19 = $4,750 in share value, plus 250
shares x $1 = $250 in distributions), but you owe tax on the $250 distribution
you received--even if you reinvest it in more shares. To avoid "buying a
dividend," check a fund's distribution schedule before you invest.


SHARE PRICE

Each Fund's share price, called its net asset value, or NAV, is calculated each
business day after the close of trading on the New York Stock Exchange (the NAV
is not calculated on holidays or other days the Exchange is closed). Net asset
value per share is computed by adding up the total value of the Fund's
investments and other assets, subtracting any of its liabilities (debts), and
then dividing by the number of Fund shares outstanding:

                                  TOTAL ASSETS   -   LIABILITIES
              NET ASSET VALUE = ----------------------------------
                                   NUMBER OF SHARES OUTSTANDING

      Knowing the daily net asset value is useful to you as a shareholder
because it indicates the current value of your investment. The Fund's NAV,
multiplied by the number of shares you own, gives you the dollar amount you
would have received had you sold all of your shares back to the Fund that day.

      A NOTE ON PRICING: A Fund's investments will be priced at their market
value when market quotations are readily available. When these quotations are
not readily available, investments will be priced at their fair value,
calculated according to procedures adopted by the Funds' Board of Trustees.

      Each Fund's share price can be found daily in the mutual fund listings of
most major newspapers under the heading
<PAGE>   29
26


"Vanguard Index Funds." Different newspapers use different abbreviations for
each Fund, but the most common are TOTST, 500, EXTND, MIDCP, SMCAP, VALUE,
SMVAL, GROWTH, and SMGTH.


                                PLAIN TALK ABOUT
                   HOW TO READ THE FINANCIAL HIGHLIGHTS TABLE

This explanation uses the Total Stock Market Index Fund as an example. The Fund
began fiscal 1998 with a net asset value (price) of $ - per share. During the
year, the Fund earned $ - per share from investment income (interest and
dividends) and $ - per share from investments that had appreciated in value or
that were sold for higher prices than the Fund paid for them.

      Shareholders received $ - per share in the form of dividend and capital
gains distributions. A portion of each year's distributions may come from the
prior year's income or capital gains.

      The earnings ($ - per share) minus the distributions ($ - per share)
resulted in a share price of $ - at the end of the year. This was an increase of
$ - per share (from $ - at the beginning of the year to $ - at the end of the
year). For a shareholder who reinvested the distributions in the purchase of
more shares, the total return from the Fund was - % for the year.

      As of December 31, 1998, the Fund had $ - billion in net assets. For the
year, its expense ratio was - % ($ - per $1,000 of net assets); and its net
investment income amounted to - % of its average net assets. It sold and
replaced securities valued at - % of its net assets.


FINANCIAL HIGHLIGHTS

The following financial highlights tables are intended to help you understand
each Fund's financial performance for the past five years*, and certain
information reflects financial results for a single Fund share in each case. The
total returns in each table represent the rate that an investor would have
earned or lost each year on an investment in the Fund (assuming reinvestment of
all dividends and distributions). This information has been derived from the
financial statements audited by PricewaterhouseCoopers LLP, independent
accountants, whose report--along with each Fund's financial statements--is
included in the Trust's most recent annual report to shareholders. You may have
the annual report sent to you without charge by contacting Vanguard.

* Because the Mid-Cap, Small-Cap Value, and Small-Cap Growth Index Funds did not
  begin operations until May 21, 1998, tables are not included for these Funds.

<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------------------------
                                                      VANGUARD TOTAL STOCK MARKET
                                                              INDEX FUND
                                                        YEAR ENDED DECEMBER 31,
- ---------------------------------------------------------------------------------------------
                                             1998     1997       1996       1995       1994
- ---------------------------------------------------------------------------------------------
<S>                                          <C>     <C>        <C>        <C>        <C>
NET ASSET VALUE, BEGINNING OF YEAR             -     $17.77     $15.04     $11.37     $11.69
- ---------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS                                                               
  Net Investment Income                        -       .319        .29        .29        .27
  Net Realized and Unrealized                                                       
   Gain (Loss) on Investments                  -      5.143       2.84       3.75       (.29)
                                             ------------------------------------------------
   Total from Investment Operations            -      5.462       3.13       4.04       (.02)
                                             ------------------------------------------------
DISTRIBUTIONS                                                                       
  Dividends from Net Investment Income         -      (.322)      (.29)      (.28)      (.27)
  Distributions from Realized Capital Gains    -      (.270)      (.11)      (.09)      (.03)
                                             ------------------------------------------------
   Total Distributions                         -      (.592)      (.40)      (.37)      (.30)
- ---------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                   -     $22.64     $17.77     $15.04     $11.37
=============================================================================================
                                                                                    
TOTAL RETURN*                                  -      30.99%     20.96%     35.79%     -0.17%
=============================================================================================
                                                                                    
RATIOS/SUPPLEMENTAL DATA                                                            
  Net Assets, End of Year (Millions)           -     $5,092     $3,531     $1,571     $  786
  Ratio of Total Expenses to                                                        
   Average Net Assets                          -       0.20%      0.22%      0.25%      0.20%
  Ratio of Net Investment Income                                                    
   to Average Net Assets                       -       1.65%      1.86%      2.14%      2.35%
  Turnover Rate                                -          2%         3%         3%         2%
- ---------------------------------------------------------------------------------------------
</TABLE>

* Total return figures do not reflect the 0.25% transaction fee on purchases
  through 1995 or the annual account maintenance fee of $10.


      From time to time, the Vanguard funds advertise yield and total return
figures. Yield is a measure of past dividend income. Total return includes both
past dividend income (assuming that it has been reinvested) plus realized and
unrealized capital appreciation (or depreciation). Neither yield nor total
return should be used to predict the future performance of a fund.
<PAGE>   30
                                                                              27


<TABLE>
<CAPTION>
- ----------------------------------------------------------------------------------------------------------
                                                                     VANGUARD 500 INDEX FUND
                                                                     YEAR ENDED DECEMBER 31,
- ----------------------------------------------------------------------------------------------------------
                                                           1998    1997       1996       1995       1994
- ----------------------------------------------------------------------------------------------------------
<S>                                                        <C>   <C>        <C>        <C>        <C>
NET ASSET VALUE, BEGINNING OF YEAR                          -    $ 69.17    $ 57.60    $ 42.97    $ 43.83
- ----------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS                                                                             
  Net Investment Income                                     -       1.31       1.28       1.22       1.18
  Net Realized and Unrealized Gain (Loss) on Investments    -      21.50      11.82      14.76       (.67)
                                                           -----------------------------------------------
   Total from Investment Operations                         -      22.81      13.10      15.98        .51
                                                           -----------------------------------------------
DISTRIBUTIONS                                                                                     
  Dividends from Net Investment Income                      -      (1.32)     (1.28)     (1.22)     (1.17)
  Distributions from Realized Capital Gains                 -       (.59)      (.25)      (.13)      (.20)
                                                           -----------------------------------------------
   Total Distributions                                      -      (1.91)     (1.53)     (1.35)     (1.37)
- ----------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                                -    $ 90.07    $ 69.17     $57.60    $ 42.97
==========================================================================================================
                                                                                                  
TOTAL RETURN*                                               -      33.19%     22.88%     37.45%     1.18%
==========================================================================================================
                                                                                                  
RATIOS/SUPPLEMENTAL DATA                                                                          
  Net Assets, End of Year (Millions)                        -    $49,358    $30,332    $17,372    $9,356
  Ratio of Total Expenses to Average Net Assets             -       0.19%      0.20%      0.20%     0.19%
  Ratio of Net Investment Income to Average Net Assets      -       1.66%      2.04%      2.38%     2.72%
  Turnover Rate**                                           -          5%         5%         4%        6%
- ----------------------------------------------------------------------------------------------------------
</TABLE>

* Total return figures do not reflect the annual account maintenance fee of $10.

** Turnover rates excluding in-kind redemptions were 1%, 3%, 2%, 2%, 4%, and 2%,
   respectively.

<TABLE>
<CAPTION>
- ----------------------------------------------------------------------------------------------------------
                                                                 VANGUARD EXTENDED MARKET INDEX FUND
                                                                       YEAR ENDED DECEMBER 31,
- ----------------------------------------------------------------------------------------------------------
                                                            1998     1997       1996      1995      1994
- ----------------------------------------------------------------------------------------------------------
<S>                                                         <C>     <C>        <C>       <C>       <C>
NET ASSET VALUE, BEGINNING OF YEAR                            -     $26.20     $24.07    $18.52    $19.43
- ----------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS                                                          
   Net Investment Income                                      -       .351        .34       .30       .28
   Net Realized and Unrealized Gain (Loss) on Investments     -      6.479       3.85      5.95      (.62)
                                                            ----------------------------------------------
      Total from Investment Operations                        -      6.830       4.19      6.25      (.34)
                                                            ----------------------------------------------
DISTRIBUTIONS                                                                  
   Dividends from Net Investment Income                       -      (.360)      (.34)     (.30)     (.28)
   Distributions from Realized Capital Gains                  -     (1.910)     (1.72)     (.40)     (.29)
                                                            ----------------------------------------------
      Total Distributions                                     -     (2.270)     (2.06)     (.70)     (.57)
- ----------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                                  -     $30.76     $26.20    $24.07    $18.52
==========================================================================================================
                                                                               
TOTAL RETURN*                                                 -      26.73%     17.65%    33.80%    -1.76%
==========================================================================================================
                                                                               
RATIOS/SUPPLEMENTAL DATA                                                       
  Net Assets, End of Year (Millions)                          -     $2,723     $2,099    $1,523    $  967
  Ratio of Total Expenses to Average Net Assets               -       0.23%      0.25%     0.25%     0.20%
  Ratio of Net Investment Income to Average Net Assets        -       1.30%      1.42%     1.51%     1.51%
  Turnover Rate                                               -         15%**      22%       15%       19%
- ----------------------------------------------------------------------------------------------------------
</TABLE>

* Total return figures do not reflect transaction fees on purchases (0.25% after
  October 31, 1997; 0.5% in 1995 through October 31, 1997; 1.0% in 1993 through
  1994) or the annual account maintenance fee of $10.

** Turnover rate excluding in-kind redemptions was 14%.
<PAGE>   31
28


<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------
                                                                     VANGUARD SMALL-CAP INDEX FUND
                                                YEAR ENDED DECEMBER 31,           FEB. 1* TO  OCT. 1, 1993, TO     YEAR ENDED
                                            1998   1997      1996     1995     DEC. 31, 1994     JAN. 31, 1994  SEP. 30, 1993
- ------------------------------------------------------------------------------------------------------------------------------
<S>                                        <C>    <C>       <C>       <C>      <C>               <C>            <C>
NET ASSET VALUE, BEGINNING OF PERIOD         -    $20.23    $18.61    $14.99          $16.24            $16.23         $12.63
- ------------------------------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS                                                                             
   Net Investment Income                     -      .277       .26       .24             .20               .05            .20
   Net Realized and Unrealized                                                                    
      Gain (Loss) on Investments             -     4.632      3.07      4.06            (.86)              .96           3.73
                                           -----------------------------------------------------------------------------------
      Total from Investment                                                                       
      Operations                             -     4.909      3.33      4.30            (.66)             1.01           3.93
                                           -----------------------------------------------------------------------------------
DISTRIBUTIONS                                                                                     
   Dividends from Net                                                                             
      Investment Income                      -     (.274)     (.27)     (.23)           (.22)             (.18)          (.18)
   Distributions from Realized                                                                    
      Capital Gains                          -    (1.115)    (1.44)     (.45)           (.37)             (.82)          (.15)
                                           -----------------------------------------------------------------------------------
      Total Distributions                    -    (1.389)    (1.71)     (.68)           (.59)            (1.00)          (.33)
- ------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD               -    $23.75    $20.23    $18.61          $14.99            $16.24         $16.23
==============================================================================================================================
                                                                                                  
TOTAL RETURN**                               -     24.59%    18.12%    28.74%          -4.00%             6.65%         31.60%
==============================================================================================================================
                                                                                                  
RATIOS/SUPPLEMENTAL DATA                                                                          
   Net Assets, End of Period (Millions)      -    $2,652    $1,713      $971            $605              $533           $432
   Ratio of Total Expenses to                                                                     
      Average Net Assets                     -      0.23%     0.25%     0.25%           0.17%+            0.18%+         0.18%
   Ratio of Net Investment Income to                                                              
      Average Net Assets                     -      1.38%     1.51%     1.58%           1.50%+            1.16%+         1.47%
   Turnover Rate                             -        29%       28%       28%             25%                5%            26%
- ------------------------------------------------------------------------------------------------------------------------------
</TABLE>

* Date of reorganization of Vanguard Small Capitalization Stock Fund into
  Vanguard Index Trust--Small Capitalization Stock Portfolio.

** Total return figures do not reflect transaction fees on purchases (0.5% after
   1996, 1.0% in 1993 through 1996) or the annual account maintenance fee of 
   $10.

+ Annualized.

<TABLE>
<CAPTION>
- -------------------------------------------------------------------------------------------------------
                                                                   VANGUARD VALUE INDEX FUND
                                                                     YEAR ENDED DECEMBER 31,
- -------------------------------------------------------------------------------------------------------
                                                           1998     1997      1996      1995      1994
- -------------------------------------------------------------------------------------------------------
<S>                                                        <C>    <C>       <C>       <C>       <C>
NET ASSET VALUE, BEGINNING OF YEAR                           -    $17.02    $14.79    $11.12    $11.74
- -------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS                                                                          
  Net Investment Income                                      -       .38       .37       .41       .38
  Net Realized and Unrealized Gain (Loss) on Investments     -      4.57      2.81      3.66      (.46)
                                                           --------------------------------------------
   Total from Investment Operations                          -      4.95      3.18      4.07      (.08)
                                                           --------------------------------------------
DISTRIBUTIONS                                                                                  
  Dividends from Net Investment Income                       -      (.37)     (.38)     (.40)     (.38)
  Distributions from Realized Capital Gains                  -      (.75)     (.57)       --      (.16)
                                                           --------------------------------------------
   Total Distributions                                       -     (1.12)     (.95)     (.40)     (.54)
- -------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                                 -    $20.85    $17.02    $14.79    $11.12
=======================================================================================================
                                                                                               
TOTAL RETURN*                                                -     29.77%    21.86%    36.94%    -0.73%
=======================================================================================================
                                                                                               
RATIOS/SUPPLEMENTAL DATA                                                                       
  Net Assets, End of Year (Millions)                         -    $1,796    $1,016      $496      $297
  Ratio of Total Expenses to Average Net Assets              -      0.20%     0.20%     0.20%     0.20%
  Ratio of Net Investment Income to Average Net Assets       -      2.05%     2.54%     3.06%     3.37%
  Turnover Rate                                              -        25%       29%       27%       32%
- -------------------------------------------------------------------------------------------------------
</TABLE>

* Total return figures do not reflect the annual account maintenance fee of $10.
<PAGE>   32
                                                                              29


<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------
                                                                  VANGUARD GROWTH INDEX FUND
                                                                    YEAR ENDED DECEMBER 31,
- -----------------------------------------------------------------------------------------------------
                                                          1998    1997      1996      1995     1994
- -----------------------------------------------------------------------------------------------------
<S>                                                       <C>    <C>       <C>       <C>      <C>
NET ASSET VALUE, BEGINNING OF YEAR                          -    $16.90    $13.97    $10.28   $10.20
- -----------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS                                                                         
  Net Investment Income                                     -       .23       .22       .21      .21
  Net Realized and Unrealized Gain (Loss) on Investments    -      5.88      3.07      3.68      .08
                                                          -------------------------------------------
   Total from Investment Operations                         -      6.11      3.29      3.89      .29
                                                          -------------------------------------------
DISTRIBUTIONS                                                                                 
  Dividends from Net Investment Income                      -      (.23)     (.22)     (.20)    (.21)
  Distributions from Realized Capital Gains                 -      (.25)     (.14)       --       --
                                                          -------------------------------------------
   Total Distributions                                      -      (.48)     (.36)     (.20)    (.21)
- -----------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                                -    $22.53    $16.90    $13.97   $10.28
=====================================================================================================
                                                                                              
TOTAL RETURN*                                               -     36.34%    23.74%    38.06%    2.89%
=====================================================================================================
                                                                                              
RATIOS/SUPPLEMENTAL DATA                                                                      
  Net Assets, End of Year (Millions)                        -    $2,365      $787      $271      $86
  Ratio of Total Expenses to Average Net Assets             -      0.20%     0.20%     0.20%    0.20%
  Ratio of Net Investment Income to Average Net Assets      -      1.19%     1.57%     1.71%    2.08%
  Turnover Rate                                             -        26%       29%       24%      28%
- -----------------------------------------------------------------------------------------------------
</TABLE>

* Total return figures do not reflect the annual account maintenance fee of $10.


"Standard & Poor's(R)," "S&P(R)," "S&P 500(R)," "Standard & Poor's 500," "500,"
"S&P MidCap 400," and "S&P SmallCap 600" are trademarks of The McGraw-Hill
Companies, Inc., and have been licensed for use by Vanguard U.S. Stock Index
Funds and The Vanguard Group. These mutual funds are not sponsored, endorsed,
sold, or promoted by Standard & Poor's, and Standard & Poor's makes no
representation regarding the advisability of investing in the Funds. "Wilshire
4500" and "Wilshire 5000" are registered trademarks of Wilshire Associates.
Frank Russell Company is the owner of the trademarks and copyrights relating to
the Russell Indexes.
<PAGE>   33
30


INVESTING WITH VANGUARD

Are you looking for the most convenient way to open or add money to a Vanguard
account? Obtain instant access to fund information? Establish an account for a
minor child or for your retirement savings?

      Vanguard can help. Our goal is to make it easy and pleasant for you to do
business with us.

      The following sections of the prospectus briefly explain the many services
we offer. Booklets providing detailed information are available on the services
marked with a [BOOK]. Please call us to request copies.


SERVICES AND ACCOUNT FEATURES

Vanguard offers many services that make it convenient to buy, sell, or exchange
shares, or to obtain fund or account information.

- --------------------------------------------------------------------------------
TELEPHONE REDEMPTIONS (SALES AND EXCHANGES)

Automatically set up for each Fund unless you notify us otherwise.
- --------------------------------------------------------------------------------
VANGUARD DIRECT DEPOSIT SERVICE(TM) [BOOK]

Automatic method for depositing your paycheck or U.S. government payment
(including Social Security and government pension checks) into your account.
- --------------------------------------------------------------------------------
VANGUARD AUTOMATIC EXCHANGE SERVICE(TM) [BOOK]

Automatic method for moving a fixed amount of money from one Vanguard fund
account to another.
- --------------------------------------------------------------------------------
VANGUARD FUND EXPRESS(R) [BOOK]

Electronic method for buying or selling shares. You can transfer money between
your Vanguard fund account and an account at your bank, savings and loan, or
credit union on a systematic schedule.
- --------------------------------------------------------------------------------
VANGUARD DIVIDEND EXPRESS(TM) [BOOK]

Electronic method for transferring dividend and/or capital gains distributions
directly from your Vanguard fund account to your bank, savings and loan, or
credit union account.
- --------------------------------------------------------------------------------
VANGUARD TELE-ACCOUNT(R) 1-800-662-6273 (ON-BOARD) [BOOK]

Toll-free 24-hour access to Vanguard fund and account information--as well as
some transactions--by using any touch-tone phone. Tele-Account provides total
return, share price, price change, and yield quotations for all Vanguard funds;
gives your account balances and history (e.g., last transaction, latest dividend
distribution); and allows you to sell or exchange fund shares.
- --------------------------------------------------------------------------------
ACCESS VANGUARD(TM) www.vanguard.com [COMPUTER]

You can use your personal computer to perform certain transactions for most
Vanguard funds by accessing our website. To establish this service, you must
register through the website. We will then send to you, by mail, an account
access password that allows you to process the following financial and
administrative transactions online:

- -     Open a new account.*

- -     Buy, sell, or exchange shares of most funds.

- -     Change your name/address.

- -     Add/change fund options (including dividend options, Vanguard Fund
      Express, bank instructions, checkwriting, and Vanguard Automatic Exchange
      Service).

* Only current Vanguard shareholders can open a new account online, by
  exchanging shares from other existing Vanguard accounts.
- --------------------------------------------------------------------------------
INVESTOR INFORMATION DEPARTMENT: 1-800-662-7447 (SHIP) TEXT TELEPHONE:
1-800-952-3335

Call Vanguard for information on our funds, fund services, and retirement
accounts, and to request literature.
- --------------------------------------------------------------------------------
CLIENT SERVICES DEPARTMENT: 1-800-662-2739 (CREW) TEXT TELEPHONE: 1-800-662-2738

Call Vanguard for information on your account, account transactions, and account
statements.
- --------------------------------------------------------------------------------
SERVICES FOR CLIENTS OF VANGUARD'S INSTITUTIONAL DIVISION: 1-888-809-8102

Vanguard's Institutional Division offers a variety of specialized services for
large institutional investors, including the ability to effect account
transactions through private electronic networks and third-party recordkeepers.
- --------------------------------------------------------------------------------
<PAGE>   34
                                                                              31


TYPES OF ACCOUNTS

Individuals and institutions can establish a variety of accounts with Vanguard.

- --------------------------------------------------------------------------------
FOR ONE OR MORE PEOPLE

Open an account in the name of one (individual) or more (joint tenants) people.
- --------------------------------------------------------------------------------
FOR HOLDING PERSONAL TRUST ASSETS [BOOK]

Invest assets held in an existing personal trust.
- --------------------------------------------------------------------------------
FOR INDIVIDUAL RETIREMENT ACCOUNTS [BOOK]

Open a traditional IRA account or a Roth IRA account. Eligibility and other
requirements are established by federal law and Vanguard custodial account
agreements. For more information, please call 1-800-662-7447 (SHIP).
- --------------------------------------------------------------------------------
FOR AN ORGANIZATION [BOOK]

Open an account as a corporation, partnership, endowment, foundation, or other
entity.
- --------------------------------------------------------------------------------
FOR THIRD-PARTY TRUSTEE RETIREMENT INVESTMENTS

Open an account as a retirement trust or plan based on an existing corporate or
institutional plan. These accounts are established by the trustee of the
existing plan.
- --------------------------------------------------------------------------------
VANGUARD PROTOTYPE PLANS

Open a variety of retirement accounts using Vanguard prototype plans for
individuals, sole proprietorships, and small businesses. For more information,
please call 1-800-662-2003.
- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------
A NOTE ON INVESTING WITH VANGUARD THROUGH OTHER FIRMS

You may purchase or sell Fund shares through a financial intermediary such as a
bank, broker, or investment adviser. If you invest with Vanguard through an
intermediary, please read that firm's program materials carefully to learn of
any special rules that may apply. For example, special terms may apply to
additional service features, fees, or other policies. Consult your intermediary
to determine when your order will be priced.
- --------------------------------------------------------------------------------


BUYING SHARES

You buy your shares at a Fund's next-determined net asset value after Vanguard
receives your request. As long as your request is received before the close of
trading on the New York Stock Exchange, generally 4 p.m. Eastern time, you will
buy your shares at that day's net asset value.
- --------------------------------------------------------------------------------
MINIMUM INVESTMENT TO . . .

open a new account

$3,000 (regular account); $1,000 (traditional IRAs and Roth IRAs).

add to an existing account

$100 by mail or exchange; $1,000 by wire.
- --------------------------------------------------------------------------------
A NOTE ON LOW BALANCES

Each Fund reserves the right to close any nonretirement account whose balance
falls below the minimum initial investment. The Fund will deduct a $10 annual
fee in June if your nonretirement account balance falls below $2,500. The fee is
waived if your total Vanguard account assets are $50,000 or more.
- --------------------------------------------------------------------------------
BY MAIL TO . . . [ENVELOPE]

open a new account

Complete and sign the application form and enclose your check.

add to an existing account

Mail your check with an Invest-By-Mail form detached from your confirmation
statement to the address listed on the form.
<PAGE>   35
32


BUYING SHARES (CONTINUED)

Make your check payable to: The Vanguard Group-(insert appropriate Fund number;
see below) 

Vanguard Total Stock Market Index Fund-85 
Vanguard 500 Index Fund-40
Vanguard Extended Market Index Fund-98 
Vanguard Mid-Cap Index Fund-859 
Vanguard Small-Cap Index Fund-48 
Vanguard Value Index Fund-06 
Vanguard Small-Cap Value Index Fund-860 
Vanguard Growth Index Fund-09 
Vanguard Small-Cap Growth Index Fund-861

All purchases must be made in U.S. dollars, and checks must be drawn on U.S.
banks.

First-class mail to:                Express or Registered mail to:
The Vanguard Group                  The Vanguard Group
P.O. Box 2600                       455 Devon Park Drive
Valley Forge, PA 19482-2600         Wayne, PA 19087-1815

- --------------------------------------------------------------------------------
IMPORTANT NOTE: To prevent check fraud, Vanguard will not accept checks made
payable to third parties.
- --------------------------------------------------------------------------------
BY TELEPHONE TO . . . [TELEPHONE]

open a new account

Call Vanguard Tele-Account* 24 hours a day--or Client Services during business
hours--to exchange from another Vanguard fund account with the same registration
(name, address, taxpayer identification number, and account type).

add to an existing account

Call Vanguard Tele-Account* 24 hours a day--or Client Services during business
hours--to exchange from another Vanguard fund account with the same registration
(name, address, taxpayer identification number, and account type). Use Vanguard
Fund Express (see "Services and Account Features") to transfer assets from your
bank account. Call Client Services before your first use to verify that this
option is in place.

Vanguard Tele-Account               Client Services
1-800-662-6273                      1-800-662-2739

* You must obtain a Personal Identification Number through Tele-Account at least
  seven days before you request your first exchange.
- --------------------------------------------------------------------------------
IMPORTANT NOTE: Once you've requested a telephone transaction and a confirmation
number has been assigned, the transaction cannot be revoked. We reserve the
right to refuse any purchase request.
- --------------------------------------------------------------------------------
BY WIRE TO OPEN A NEW ACCOUNT OR ADD TO AN EXISTING ACCOUNT [WIRE]

Call Client Services to arrange your wire transaction. Wire transactions are not
available for retirement accounts, except for asset transfers and direct
rollovers.

Wire to:
FRB ABA 021001088
Marine Midland Bank, New York

For credit to:
Account: 000112046
Vanguard Incoming Wire Account
<PAGE>   36
                                                                              33


In favor of:

Vanguard Total Stock Market Index Fund-85
Vanguard 500 Index Fund-40 
Vanguard Extended Market Index Fund-98 
Vanguard Mid-Cap Index Fund-859 
Vanguard Small-Cap Index Fund-48 
Vanguard Value Index Fund-06 
Vanguard Small-Cap Value Index Fund-860 
Vanguard Growth Index Fund-09
Vanguard Small-Cap Growth Index Fund-861
[Account number, or temporary number for a new account]
[Registered account owner/s]
[Registered address]
- --------------------------------------------------------------------------------
      You can redeem (that is, sell or exchange) shares purchased by check or
Vanguard Fund Express at any time. However, while your redemption request will
be processed at the next-determined net asset value after it is received, your
redemption proceeds will not be available until payment for your purchase is
collected, which may take up to ten calendar days.
- --------------------------------------------------------------------------------
A NOTE ON LARGE PURCHASES

It is important that you call Vanguard before you invest a large dollar amount.
We must consider the interests of all Fund shareholders and so reserve the right
to refuse any purchase that will disrupt the Fund's operation or performance.
- --------------------------------------------------------------------------------


REDEEMING SHARES

This section describes how you can redeem--that is, sell or exchange--a Fund's
shares.

When Selling Shares:

- -     Vanguard sends the redemption proceeds to you or a designated third
      party.*

- -     You can sell all or part of your Fund shares at any time.

* Proceeds sent to third parties require a signature guarantee; see footnote on
  page 35.

When Exchanging Shares:

- -     The redemption proceeds are used to purchase shares of a different
      Vanguard fund.

- -     You must meet the receiving fund's minimum investment requirements.

- -     Vanguard reserves the right to revise or terminate the exchange privilege,
      limit the amount of an exchange, or reject an exchange at any time,
      without notice.

In both cases, your transaction will be based on the Fund's next-determined
share price, subject to any special rules discussed in this prospectus. For
exchanges, the purchase side of the transaction will be based on the receiving
fund's next-determined share price, again subject to any special rules discussed
in this prospectus.
- --------------------------------------------------------------------------------
NOTE: Once a redemption is processed and a confirmation number given, the
transaction CANNOT be canceled.
- --------------------------------------------------------------------------------

HOW TO REQUEST A REDEMPTION

You can request a redemption from your Fund account in any one of three ways:
online (only for IRAs and other retirement accounts), by telephone (sell, but
not exchange), or by mail.
- --------------------------------------------------------------------------------
<PAGE>   37
34


REDEEMING SHARES (continued)

- --------------------------------------------------------------------------------
ONLINE REQUESTS [COMPUTER]

ACCESS VANGUARD at www.vanguard.com

You can use your personal computer to sell or exchange shares of most Vanguard
funds by accessing our website. To establish this service, you must register
through the website. We will then send you, by mail, an account access password
that will enable you to sell or exchange shares online (as well as perform other
transactions).

      NOTE: The Vanguard funds whose shares you cannot exchange online or by
telephone are VANGUARD U.S. STOCK INDEX FUNDS, VANGUARD BALANCED INDEX FUND,
VANGUARD INTERNATIONAL STOCK INDEX FUNDS, VANGUARD REIT INDEX FUND, VANGUARD
TOTAL INTERNATIONAL STOCK INDEX FUND, and VANGUARD GROWTH AND INCOME FUND. These
funds do, however, permit online and telephone exchanges within IRAs and other
retirement accounts. If you sell shares of these funds online, you will receive
a redemption check at your address of record.
- --------------------------------------------------------------------------------
TELEPHONE REQUESTS [TELEPHONE]

All Account Types Except Retirement:

Call Vanguard Tele-Account 24 hours a day--or Client Services during business
hours--to sell shares.

Retirement Accounts:

You can exchange--but not sell--shares by calling Tele-Account or Client
Services.

Vanguard Tele-Account               Client Services
1-800-662-6273                      1-800-662-2739
- --------------------------------------------------------------------------------
SPECIAL INFORMATION: We will automatically establish the telephone redemption
option for your account, unless you instruct us otherwise in writing. While
telephone redemption is easy and convenient, this account feature involves a
risk of loss from unauthorized or fraudulent transactions. Vanguard will take
reasonable precautions to protect your account from fraud. You should do the
same by keeping your account information private and immediately reviewing any
account statements that we send to you. Make sure to contact Vanguard
immediately about any transaction you believe to be unauthorized.
- --------------------------------------------------------------------------------
      We reserve the right to refuse a telephone redemption if the caller is 
unable to provide:

[CHECKMARK] The ten-digit account number.

[CHECKMARK] The name and address exactly as registered on the account.

[CHECKMARK] The primary Social Security or employer identification number as 
            registered on the account.

[CHECKMARK] The Personal Identification Number, if applicable.

      Please note that Vanguard will not be responsible for any account losses
due to telephone fraud, so long as we have taken reasonable steps to verify the
caller's identity. If you wish to remove the telephone redemption feature from
your account, please notify us in writing.
- --------------------------------------------------------------------------------
A NOTE ON UNUSUAL CIRCUMSTANCES

Vanguard reserves the right to revise or terminate the telephone redemption
privilege at any time, without notice. In addition, Vanguard can stop selling
shares or postpone payment at times when the New York Stock Exchange is closed
or under any emergency circumstances as determined by the U.S. Securities and
Exchange Commission. If you experience difficulty making a telephone redemption
during periods of drastic economic or market change, you can send us your
request by regular or express mail. Follow the instructions on selling or
exchanging shares by mail in this section.
- --------------------------------------------------------------------------------
MAIL REQUESTS [ENVELOPE]

All Account Types Except Retirement:

Send a letter of instruction signed by all registered account holders. Include
the fund name and account number and (if you are selling) a dollar amount or
number of shares OR (if you are exchanging) the name of the fund you want to
exchange into and a dollar amount or number of shares. To exchange into an
account with a different registration (including a different name, address,
taxpayer identification number, or account type), you must provide Vanguard with
written instructions that include the guaranteed signatures of all current
owners of the fund from which you wish to redeem.
<PAGE>   38
                                                                              35


Vanguard Retirement Accounts:

For information on how to request distributions from:

- -     Traditional IRAs and Roth IRAs--call Client Services.

- -     SEP-IRAs, SIMPLE IRAs, 403(b)(7) custodial accounts, and Profit-Sharing
      and Money Purchase Pension (Keogh) Plans--call Individual Retirement Plans
      at 1-800-662-2003.

Depending on your account registration type, additional documentation may be
required.

First-class mail to:                Express or Registered mail to:
The Vanguard Group                  The Vanguard Group
P.O. Box 1120                       455 Devon Park Drive
Valley Forge, PA 19482-1120         Wayne, PA 19087-1815

For clients of Vanguard's Institutional Division...

First-class mail to:                Express or Registered mail to:
The Vanguard Group                  The Vanguard Group
P.O. Box 2900                       455 Devon Park Drive
Valley Forge, PA 19482-2900         Wayne, PA 19087-1815
- --------------------------------------------------------------------------------
A NOTE ON LARGE REDEMPTIONS

It is important that you call Vanguard before you redeem a large dollar amount.
We must consider the interests of all fund shareholders and so reserve the right
to delay delivery of your redemption proceeds--up to seven days--if the amount
will disrupt the Fund's operation or performance.

      If you redeem more than $250,000 worth of Fund shares within any 90-day
period, the Fund reserves the right to pay part or all of the redemption
proceeds above $250,000 in kind, i.e., in securities, rather than in cash. If
payment is made in kind, you may incur brokerage commissions if you elect to
sell the securities for cash.
- --------------------------------------------------------------------------------

OPTIONS FOR REDEMPTION PROCEEDS

You may receive your redemption proceeds in one of two ways: check, or exchange
to another Vanguard fund.
- --------------------------------------------------------------------------------
CHECK REDEMPTIONS

Normally, Vanguard will mail your check within two business days of a
redemption.
- --------------------------------------------------------------------------------
EXCHANGE REDEMPTIONS

As described above, an exchange involves using the proceeds of your redemption
to purchase shares of another Vanguard fund.
- --------------------------------------------------------------------------------

FOR OUR MUTUAL PROTECTION

For your best interests and ours, Vanguard applies these additional requirements
to redemptions:

REQUEST IN "GOOD ORDER"

All redemption requests must be received by Vanguard in "good order." This means
that your request must include:

[CHECKMARK] The Fund name and account number.

[CHECKMARK] The amount of the transaction (in dollars or shares).

[CHECKMARK] Signatures of all owners exactly as registered on the account (for 
            mail requests).

[CHECKMARK] Signature guarantees (if required).*

[CHECKMARK] Any supporting legal documentation that may be required.

[CHECKMARK] Any outstanding certificates representing shares to be redeemed.

* For instance, a signature guarantee must be provided by all registered account
  shareholders when redemption proceeds are to be sent to a different person or
  address. A signature guarantee can be obtained from most banks, credit unions,
  and licensed brokers.

TRANSACTIONS ARE PROCESSED AT THE NEXT-DETERMINED SHARE PRICE AFTER VANGUARD HAS
RECEIVED ALL REQUIRED INFORMATION.
- --------------------------------------------------------------------------------
<PAGE>   39
36


REDEEMING SHARES (continued)

- --------------------------------------------------------------------------------
LIMITS ON ACCOUNT ACTIVITY

Because excessive account transactions can disrupt management of a Fund and
increase the Fund's costs for all shareholders, Vanguard limits account activity
as follows: 

- -     You may make no more than TWO SUBSTANTIVE "ROUND TRIPS" THROUGH THE FUND
      during any 12-month period.

- -     Your round trips through the Fund must be at least 30 days apart.

- -     The Fund may refuse a share purchase at any time, for any reason.

- -     Vanguard may revoke an investor's telephone exchange privilege at any
      time, for any reason.

A "round trip" is a redemption from the Fund followed by a purchase back into
the Fund. Also, "round trip" covers transactions accomplished by any combination
of methods, including transactions conducted by check, wire, or exchange to/from
another Vanguard fund. "Substantive" means a dollar amount that Vanguard
determines, in its sole discretion, could adversely affect the management of the
Fund.
- --------------------------------------------------------------------------------
RETURN YOUR SHARE CERTIFICATES

Any portion of your account represented by share certificates cannot be redeemed
until you return the certificates to Vanguard. Certificates must be returned
(unsigned), along with a letter requesting the sale or exchange you wish to
process, via certified mail to:

The Vanguard Group
455 Devon Park Drive
Wayne, PA 19087-1815
- --------------------------------------------------------------------------------
ALL TRADES FINAL

Vanguard will not cancel any transaction request (including any purchase or
redemption) that we believe to be authentic once the request has been received
and a confirmation number assigned.
- --------------------------------------------------------------------------------

TRANSFERRING REGISTRATION

You can transfer the registration of your Fund shares to another owner by
completing a transfer form and sending it to Vanguard.

First-class mail to:                Express or Registered mail to:
The Vanguard Group                  The Vanguard Group
P.O. Box 1100                       455 Devon Park Drive
Valley Forge, PA 19482-1100         Wayne, PA 19087-1815

For clients of Vanguard's Institutional Division . . .

First-class mail to:                Express or Registered mail to:
The Vanguard Group                  The Vanguard Group
P.O. Box 2900                       455 Devon Park Drive
Valley Forge, PA 19482-2900         Wayne, PA 19087-1815
- --------------------------------------------------------------------------------
<PAGE>   40
                                                                              37


FUND AND ACCOUNT UPDATES

STATEMENTS AND REPORTS

We will send you account and tax statements to help you keep track of your Fund
account throughout the year as well as when you are preparing your income tax
returns.

      In addition, you will receive financial reports about a Fund twice a year.
These comprehensive reports include an assessment of the Fund's performance (and
a comparison to its industry benchmark), an overview of the markets, a report
from the advisers, and the Fund's financial statements which include a listing
of the Fund's holdings.

      To keep each Fund's costs as low as possible (so that you and other
shareholders can keep more of the Fund's investment earnings), Vanguard attempts
to eliminate duplicate mailings to the same address. When we find that two or
more Fund shareholders have the same last name and address, we send just one
Fund report to that address--instead of mailing separate reports to each
shareholder. If you want us to send separate reports, however, you may notify
our Investor Information Department at 1-800-662-7447.

- --------------------------------------------------------------------------------
CONFIRMATION STATEMENT

Sent each time you buy, sell, or exchange shares; confirms the trade date and
the amount of your transaction.
- --------------------------------------------------------------------------------
PORTFOLIO SUMMARY [BOOK GRAPHIC]

Mailed quarterly for most accounts; shows the market value of your account at
the close of the statement period, as well as distributions, purchases, sales,
and exchanges for the current calendar year.
- --------------------------------------------------------------------------------
FUND FINANCIAL REPORTS

Mailed in February and August for all nine Funds.
- --------------------------------------------------------------------------------
TAX STATEMENTS

Generally mailed in January; report previous year's dividend and capital gains
distributions, proceeds from the sale of shares, and distributions from IRAs or
other retirement accounts.
- --------------------------------------------------------------------------------
AVERAGE COST REVIEW STATEMENT [BOOK GRAPHIC]

Issued quarterly for most taxable accounts (accompanies your Portfolio Summary);
shows the average cost of shares that you redeemed during the calendar year,
using the average cost single category method.
- --------------------------------------------------------------------------------
<PAGE>   41
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<PAGE>   42
                      (This page intentionally left blank.)
<PAGE>   43
                      (This page intentionally left blank.)










<PAGE>   44
GLOSSARY OF INVESTMENT TERMS

ACTIVE MANAGEMENT

An investment approach that seeks to exceed the average returns of the financial
markets. Active managers rely on research, market forecasts, and their own
judgment and experience in selecting securities to buy and sell.

CAPITAL GAINS DISTRIBUTION

Payment to mutual fund shareholders of gains realized on securities that the
fund has sold at a profit, minus any realized losses.

CASH RESERVES

Cash deposits, short-term bank deposits, and money market instruments which
include U.S. Treasury bills, bank certificates of deposit (CDs), repurchase
agreements, commercial paper, and banker's acceptances.

COMMON STOCK

A security representing ownership rights in a corporation. A stockholder is
entitled to share in the company's profits, some of which may be paid out as
dividends.

DIVIDEND INCOME

Payment to shareholders of income from interest or dividends generated by a
fund's investments.

DOLLAR-COST AVERAGING

Investing equal amounts of money at regular intervals on an ongoing basis. This
technique ensures that an investor buys fewer shares when prices are high and
more shares when prices are low.

EXPENSE RATIO

The percentage of a fund's average net assets used to pay its expenses. The
expense ratio includes management fees, administrative fees, and any 12b-1
marketing fees.

INDEX

An unmanaged group of securities whose overall performance is used as a standard
to measure investment performance.

INVESTMENT ADVISER

An organization that makes the day-to-day decisions regarding a fund's
investments.

MUTUAL FUND

An investment company that pools the money of many people and invests it in a
variety of securities in an effort to achieve a specific objective over time.

NET ASSET VALUE (NAV)

The market value of a mutual fund's total assets, minus liabilities, divided by
the number of shares outstanding. The value of a single share is called its
share value or share price.

PASSIVE MANAGEMENT

A low-cost investment strategy in which a mutual fund attempts to match--rather
than outperform--a particular stock or bond market index. Also known as
indexing.

PRINCIPAL

The amount of your own money you put into an investment.

SECURITIES

Stocks, bonds, money market instruments, and other investment vehicles.

TOTAL RETURN

A percentage change, over a specified time period, in a mutual fund's net asset
value, with the ending net asset value adjusted to account for the reinvestment
of all distributions of dividends and capital gains.

VOLATILITY

The fluctuations in value of a mutual fund or other security. The greater a
fund's volatility, the wider the fluctuations between its high and low prices.

YIELD

Income (interest or dividends) earned by an investment, expressed as a
percentage of the investment's price.
<PAGE>   45
[VANGUARD GROUP LOGO]
Post Office Box 2600
Valley Forge, PA 19482-2600


FOR MORE INFORMATION

If you'd like more information about Vanguard U.S. Stock Index Funds, the
following documents are available free upon request:

ANNUAL/SEMIANNUAL REPORT TO SHAREHOLDERS

Additional information about the Funds' investments is available in the Funds'
annual and semiannual reports to shareholders. In these reports, you will find a
discussion of the market conditions and investment strategies that significantly
affected the performance of the Funds' during the most recent fiscal year.

STATEMENT OF ADDITIONAL INFORMATION (SAI) 

The SAI provides more detailed information about the Funds.

The current annual and semiannual reports and the SAI are incorporated by
reference into (and are thus legally a part of) this prospectus.

To receive a free copy of the latest annual or semiannual report or the SAI, or
to request additional information about the Funds or other Vanguard funds,
please contact us as follows:

THE VANGUARD GROUP
INVESTOR INFORMATION 
DEPARTMENT
P.O. BOX 2600
VALLEY FORGE, PA 19482-2600

TELEPHONE:
1-800-662-7447 (SHIP)

TEXT TELEPHONE:
1-800-952-3335

WORLD WIDE WEB:
WWW.VANGUARD.COM

If you are a current shareholder of any of the Funds and would like information
about your account, account transactions, and/or account statements, please
call:

CLIENT SERVICES DEPARTMENT:         
TELEPHONE:
1-800-662-2739 (CREW)

TEXT TELEPHONE:
1-800-662-2738

INFORMATION PROVIDED BY THE SECURITIES AND EXCHANGE COMMISSION (SEC)

You can review and copy information about the Funds (including the SAI) at the
SEC's Public Reference Room in Washington, D.C. To find out more about this
public service, call the SEC at 1-800-SEC-0330. Reports and other information
about the Funds are also available on the SEC's website (www.sec.gov), or you
can receive copies of this information, for a fee, by writing the Public
Reference Section, Securities and Exchange Commission, Washington, DC
20549-6009.

Funds' Investment Company Act file number: 811-2652


(C) 1999 The Vanguard Group, Inc.
All rights reserved.
Vanguard Marketing
Corporation, Distributor.

P040N-04/26/1999
    
<PAGE>   46
   
VANGUARD U.S. STOCK INDEX FUNDS
Participant Prospectus
April 26, 1999


CONTENTS


1  AN INTRODUCTION TO INDEX FUNDS

2  FUND PROFILES

   2  Vanguard Total Stock Market Index Fund

   4  Vanguard 500 Index Fund

   6  Vanguard Extended Market Index Fund

   8  Vanguard Mid-Cap Index Fund

   10 Vanguard Small-Cap Index Fund

   12 Vanguard Value Index Fund

   14 Vanguard Small-Cap Value Index Fund

   16 Vanguard Growth Index Fund

   18 Vanguard Small-Cap Growth Index Fund

20 MORE ON THE FUNDS

23 THE FUNDS AND VANGUARD

23 INVESTMENT ADVISER

24 YEAR 2000 CHALLENGE

24 DIVIDENDS, CAPITAL GAINS, AND TAXES

25 SHARE PRICE

26 FINANCIAL HIGHLIGHTS

30 INVESTING WITH VANGUARD

30 ACCESSING FUND INFORMATION BY COMPUTER

GLOSSARY (inside back cover)


WHY READING THIS PROSPECTUS IS IMPORTANT

This prospectus explains the objective, risks, and strategies of each of the
Vanguard U.S. Stock Index Funds. To highlight terms and concepts important to
mutual fund investors, we have provided "Plain Talk(R)" explanations along the
way. Reading the prospectus will help you to decide which Funds, if any, are the
right investments for you. We suggest that you keep it for future reference.

IMPORTANT NOTE

Each of the Vanguard U.S. Stock Index Funds offers two separate classes of
shares: Investor and Institutional (except Vanguard 500 Index Fund, which offers
only Investor Shares). Investor Shares, which have an investment minimum of
$3,000, are offered by two separate prospectuses. This prospectus is intended
for participants in employer-sponsored retirement or savings plans. Another
version -- for investors who would like to open a personal investment account --
can be obtained by calling Vanguard at 1-800-662-7447. Institutional Shares have
an investment minimum of $10 million and generally do not require special
employee benefit plan services. These Shares are offered by another prospectus
(you can obtain a copy of the Institutional Shares prospectus by calling
Vanguard's Institutional Investor Group at 1-800-523-1036). Note that the Funds'
separate share classes have different expenses; as a result, their investment
performance will vary.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.
<PAGE>   47
                                                                              1


   This prospectus provides information about the nine Vanguard U.S. Stock Index
Funds. After the introduction below, you'll find profiles that summarize key
features of each Fund. Following the profiles, there is important additional
information common to all of the Funds.


AN INTRODUCTION TO INDEX FUNDS

WHAT IS INDEXING?

An index is an unmanaged group of securities whose overall performance is used
as a standard to measure investment performance. An index (or "passively
managed") fund tries to match, as closely as possible, the performance of an
established target index. The fund does this by holding all, or a representative
sample, of the securities in the index.

   Index funds may seek to track indexes that hold a certain type of stock
- --such as growth or value, small-cap or large-cap, or those from just one
industry -- or they may seek to track indexes that consist of a broader range of
stocks -- for example, the entire U.S. stock market.

   Index funds are not actively managed by investment advisers who buy and sell
securities based on research and analysis, in an attempt to outperform the
market as a whole. Rather, index funds simply mirror what the target index does,
for better or worse.

WHY INVEST IN INDEX FUNDS?

Index funds appeal to many investors for a number of reasons:

- -  Simplicity. Indexing is a straightforward market-matching strategy.

- -  Diversification. Indexes generally cover a wide variety of companies and
   industries.

- -  Relative performance predictability. An index fund is expected to closely
   parallel the performance of its target index.

- -  Low cost. Index funds do not have many of the expenses of an actively managed
   fund -- such as research -- and keep trading activity, and thus brokerage
   commissions, to a minimum.

- -  Low realization of capital gains. Because an index fund typically sells
   securities only to respond to redemption requests or to adjust the number of
   shares it holds to reflect a change in its target index, the fund's turnover
   rate -- and thus its realization of taxable capital gains -- is usually very
   low.

   Keep in mind that an index fund has operating expenses and transaction costs;
a market index does not. Therefore, an index fund -- while expected to track its
target index as closely as possible -- will typically be unable to match the
performance of the index exactly.

   For more information about index funds, see "Indexing Methods" under MORE ON
THE FUNDS.

- --------------------------------------------------------------------------------
                                PLAIN TALK ABOUT
                             THE COSTS OF INVESTING

Costs are an important consideration in choosing a mutual fund. That's because
you, as a shareholder, pay the costs of operating a fund, plus any transaction
costs associated with the fund's buying and selling of securities. These costs
can erode a substantial portion of the gross income or capital appreciation a
fund achieves. Even seemingly small differences in fund expenses can, over time,
have a dramatic effect on a fund's performance.
- --------------------------------------------------------------------------------
<PAGE>   48
2


FUND PROFILE -- VANGUARD TOTAL STOCK MARKET INDEX FUND

The following profile summarizes key features of Vanguard Total Stock Market
Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of the overall stock market.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Wilshire 5000 Equity Index, which consists of all the U.S. common stocks
regularly traded on the New York and American Stock Exchanges and the Nasdaq
over-the-counter market.

PRIMARY RISK

THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
Stock markets tend to move in cycles, with periods of rising prices and periods
of falling prices.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year since
the Fund's inception. The table shows how the Fund's average annual returns for
one and five calendar years and since inception compare with those of the index
that the Fund seeks to track. Keep in mind that the Fund's past performance does
not indicate how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------




- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                          1 YEAR    5 YEARS    SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                       <C>       <C>        <C>
Vanguard Total Stock Market Index Fund       - %        - %           - %
Wilshire 5000 Index                          -          -             -
- --------------------------------------------------------------------------------
*April 27, 1992.
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   49
                                                                               3

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                        <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        None
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      Annual Fund Operating Expenses (expenses deducted from the
       Fund's assets)
      Management Expenses:                                                   - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                        - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                - %
</TABLE>


   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($2.50 each quarter) from your quarterly distribution
of the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
April 27, 1992

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
TotSt

VANGUARD FUND NUMBER
085

CUSIP NUMBER
922908306

TICKER SYMBOL
VTSMX
- --------------------------------------------------------------------------------
<PAGE>   50
4


FUND PROFILE -- VANGUARD 500 INDEX FUND

The following profile summarizes key features of Vanguard 500 Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's 500 Composite Stock Price Index, which is dominated by
the stocks of large U.S. companies.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from large-capitalization stocks will trail returns from other asset
   classes or the overall stock market. Large-capitalization stocks tend to go
   through cycles of doing better -- or worse -- than the stock market in
   general. These periods have, in the past, lasted for as long as several
   years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year over
a ten-year period. The table shows how the Fund's average annual returns for
one, five, and ten calendar years compare with those of the index that the Fund
seeks to track. Keep in mind that the Fund's past performance does not indicate
how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------





- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
        AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
                                          1 YEAR    5 YEARS        10 YEARS
- --------------------------------------------------------------------------------
<S>                                       <C>       <C>        <C>
Vanguard 500 Index Fund                      - %        - %           - %
S&P 500 Index                                -          -             -
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   51
                                                                               5

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                        <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        None
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
       assets)
      Management Expenses:                                                   - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                        - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                - %
</TABLE>

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($2.50 each quarter) from your quarterly distribution
of the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>


  THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
August 31, 1976

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
500

VANGUARD FUND NUMBER
040

CUSIP NUMBER
922908108

TICKER SYMBOL
VFINX
- --------------------------------------------------------------------------------
<PAGE>   52
6


FUND PROFILE -- VANGUARD EXTENDED MARKET INDEX FUND

The following profile summarizes key features of Vanguard Extended Market Index
Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of mid- and small-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Wilshire 4500 Equity Index, a broadly diversified index of stocks of
medium-size and small U.S. companies. The Wilshire 4500 Index contains all of
the U.S. common stocks regularly traded on the New York and American Stock
Exchanges and the Nasdaq over-the-counter market, except those stocks included
in the S&P 500 Index.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from mid- or small-capitalization stocks will trail returns from
   other asset classes or the overall stock market. Each type of stock tends to
   go through cycles of doing better -- or worse -- than the stock market in
   general. These periods have, in the past, lasted for as long as several
   years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year over
a ten-year period. The table shows how the Fund's average annual returns for
one, five, and ten calendar years compare with those of the index that the Fund
seeks to track. Keep in mind that the Fund's past performance does not indicate
how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------





- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000, or the transaction fee of 0.25%
on purchases.
- --------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).

- --------------------------------------------------------------------------------


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
        AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                          1 YEAR    5 YEARS      10 YEARS
- --------------------------------------------------------------------------------
<S>                                       <C>       <C>        <C>
Vanguard Extended Market Index Fund          - %        - %           - %
Wilshire 4500 Index                          -          -             -
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   53
                                                                               7

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                        <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        0.25%*
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
       assets)
      Management Expenses:                                                    - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                         - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                 - %
</TABLE>

      *  The transaction fee is deducted from all purchases (including exchanges
         from other Vanguard funds), but not from reinvested dividends and
         capital gains.

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($10 each December) from your annual distribution of
the Fund's dividends. If your distribution is less than the fee, fractional
shares will automatically be redeemed to make up the difference.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
December 21, 1987

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
Extnd

VANGUARD FUND NUMBER
098

CUSIP NUMBER
922908207

TICKER SYMBOL
VEXMX
- --------------------------------------------------------------------------------
<PAGE>   54
8


FUND PROFILE -- VANGUARD MID-CAP INDEX FUND

The following profile summarizes key features of Vanguard Mid-Cap Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of mid-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's MidCap 400 Index, which is made up of a group of
medium-size U.S. companies.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from mid-capitalization stocks will trail returns from other asset
   classes or the overall stock market. Mid-capitalization stocks tend to go
   through cycles of doing better -- or worse -- than the stock market in
   general. These periods have, in the past, lasted for as long as several
   years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                         <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        0.25%*
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
       assets)
      Management Expenses:                                                    - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                         - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                 - %
</TABLE>

      *  The transaction fee is deducted from all purchases (including exchanges
         from other Vanguard funds), but not from reinvested dividends and
         capital gains.

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($10 each December) from your annual distribution of
the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.
<PAGE>   55
                                                                               9


   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
MidCp

VANGUARD FUND NUMBER
859

CUSIP NUMBER
922908843

TICKER SYMBOL
VIMSX
- --------------------------------------------------------------------------------
<PAGE>   56
10


FUND PROFILE -- VANGUARD SMALL-CAP INDEX FUND

The following profile summarizes key features of Vanguard Small-Cap Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Russell 2000 Small Stock Index, which is made up of the stocks of smaller
U.S. companies. The Russell 2000 Index is comprised of the 2,000 smallest
companies out of the 3,000 largest U.S. companies.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from small-capitalization stocks will trail returns from other asset
   classes or the overall stock market. Small-capitalization stocks tend to go
   through cycles of doing better -- or worse -- than the stock market in
   general. These periods have, in the past, lasted for as long as several
   years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year over
a ten-year period. The table shows how the Fund's average annual returns for
one, five, and ten calendar years compare with those of the index that the Fund
seeks to track. Keep in mind that the Fund's past performance does not indicate
how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------





- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000, or the transaction fee of 0.50%
on purchases.
- --------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
        AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                          1 YEAR    5 YEARS      10 YEARS
- --------------------------------------------------------------------------------
<S>                                       <C>       <C>        <C>
Vanguard Small-Cap Index Fund                - %        - %           - %
Russell 2000 Index                           -          -             -
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   57
                                                                              11

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                        <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        0.50%*
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
       assets)
      Management Expenses:                                                    - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                         - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                 - %
</TABLE>

      *  The transaction fee is deducted from all purchases (including exchanges
         from other Vanguard funds), but not from reinvested dividends and
         capital gains.

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($10 each December) from your annual distribution of
the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>

  THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
October 3, 1960

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
SmCap

VANGUARD FUND NUMBER
048

CUSIP NUMBER
922908702

TICKER SYMBOL
NAESX
- --------------------------------------------------------------------------------
<PAGE>   58
12


FUND PROFILE -- VANGUARD VALUE INDEX FUND

The following profile summarizes key features of Vanguard Value Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization value stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's/BARRA Value Index, which includes those stocks of the
S&P 500 Index with lower than average price/book ratios.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from value stocks will trail returns from other asset classes or the
   overall stock market. Value stocks tend to go through cycles of doing better
   --or worse -- than the stock market in general. These periods have, in the
   past, lasted for as long as several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year since
the Fund's inception. The table shows how the Fund's average annual returns for
one and five calendar years and since inception compare with those of the index
that the Fund seeks to track. Keep in mind that the Fund's past performance does
not indicate how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------







- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
        AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                          1 YEAR    5 YEARS    SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                       <C>       <C>        <C>
Vanguard Value Index Fund                    - %        - %           - %
S&P/BARRA Value Index                        -          -             -
- --------------------------------------------------------------------------------
*November 2, 1992.
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   59
                                                                              13


FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                        <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        None
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
        assets)
      Management Expenses:                                                    - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                         - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                 - %
</TABLE>

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($2.50 each quarter) from your quarterly distribution
of the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>

  THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
November 2, 1992

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
Value

VANGUARD FUND NUMBER
006

CUSIP NUMBER
922908405

TICKER SYMBOL
VIVAX
- --------------------------------------------------------------------------------
<PAGE>   60
14


FUND PROFILE -- VANGUARD SMALL-CAP VALUE INDEX FUND

The following profile summarizes key features of Vanguard Small-Cap Value Index
Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization value stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's SmallCap 600/BARRA Value Index, which includes those
stocks of the S&P SmallCap 600 Index with lower than average price/book ratios.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from small-capitalization value stocks will trail returns from other
   asset classes or the overall stock market. Small-capitalization value stocks
   tend to go through cycles of doing better -- or worse -- than the stock
   market in general. These periods have, in the past, lasted for as long as
   several years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                         <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        1.00%*
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
        assets)
      Management Expenses:                                                    - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                         - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                 - %
</TABLE>

      *  The transaction fee is deducted from all purchases (including exchanges
         from other Vanguard funds), but not from reinvested dividends and
         capital gains.

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($10 each December) from your annual distribution of
the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.
<PAGE>   61
                                                                              15

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa.,since inception

INCEPTION DATE
May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
SmVal

VANGUARD FUND NUMBER
860

CUSIP NUMBER
922908793

TICKER SYMBOL
VISVX
- --------------------------------------------------------------------------------
<PAGE>   62
16


FUND PROFILE -- VANGUARD GROWTH INDEX FUND

The following profile summarizes key features of Vanguard Growth Index Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization growth stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's/BARRA Growth Index, which includes those stocks of the
S&P 500 Index with higher than average price/book ratios.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from growth stocks will trail returns from other asset classes or the
   overall stock market. Growth stocks tend to go through cycles of doing better
   -- or worse -- than the stock market in general. These periods have, in the
   past, lasted for as long as several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the Fund's performance in each calendar year since
the Fund's inception. The table shows how the Fund's average annual returns for
one and five calendar years and since inception compare with those of the index
that the Fund seeks to track. Keep in mind that the Fund's past performance does
not indicate how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------






- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
        AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                          1 YEAR    5 YEARS    SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                       <C>       <C>        <C>
Vanguard Growth Index Fund                   - %        - %           - %
S&P/BARRA Growth Index                       -          -             -
- --------------------------------------------------------------------------------
*November 2, 1992.
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   63
                                                                              17

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.


<TABLE>
<S>                                                                        <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        None
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
       assets)
      Management Expenses:                                                    - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                         - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                 - %
</TABLE>

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($2.50 each quarter) from your annual distribution of
the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.



- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
November 2, 1992

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
Growth

VANGUARD FUND NUMBER
009

CUSIP NUMBER
922908504

TICKER SYMBOL
VIGRX
- --------------------------------------------------------------------------------
<PAGE>   64
18


FUND PROFILE -- VANGUARD SMALL-CAP GROWTH INDEX FUND

The following profile summarizes key features of Vanguard Small-Cap Growth Index
Fund.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization growth stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's SmallCap 600/BARRA Growth Index, which includes those
stocks of the S&P SmallCap 600 Index with higher than average price/book ratios.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from small-capitalization growth stocks will trail returns from other
   asset classes or the overall stock market. Small-capitalization growth stocks
   tend to go through cycles of doing better -- or worse -- than the stock
   market in general. These periods have, in the past, lasted for as long as
   several years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                         <C>
      SHAREHOLDER FEES (fees paid directly from your investment)
      Sales Charge (Load) Imposed on Purchases:                             None
      Transaction Fees on Purchases:                                        1.00%*
      Sales Charge (Load) Imposed on Reinvested Dividends:                  None
      Redemption Fees:                                                      None
      Exchange Fees:                                                        None

      ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
       assets)
      Management Expenses:                                                    - %
      12b-1 Marketing Fees:                                                 None
      Other Expenses:                                                         - %
        TOTAL ANNUAL FUND OPERATING EXPENSES:                                 - %
</TABLE>


      *  The transaction fee is deducted from all purchases (including exchanges
         from other Vanguard funds), but not from reinvested dividends and
         capital gains.

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($10 each December) from your annual distribution of
the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.
<PAGE>   65
                                                                              19


   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
          1 YEAR      3 YEARS      5 YEARS    10 YEARS
- --------------------------------------------------------------------------------
<S>                   <C>          <C>         <C>
           $ -          $ -          $ -         $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.


- --------------------------------------------------------------------------------
ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
SmGth

VANGUARD FUND NUMBER
861

CUSIP NUMBER
922908827

TICKER SYMBOL
 VISGX
- --------------------------------------------------------------------------------
<PAGE>   66
20


MORE ON THE FUNDS

The following sections discuss other important features of Vanguard U.S.
Stock Index Funds.

INDEXING METHODS

In seeking to track a particular index, a fund generally uses one of two methods
to select stocks.

   Some index funds hold each stock found in their target indexes in about the
same proportions as represented in the indexes themselves. This is called a
"replication" method. For example, if 5% of the S&P 500 Index were made up of
the stock of a specific company, a fund tracking that index (such as Vanguard
500 Index Fund) would invest about 5% of its assets in that company. The 500,
Mid-Cap, Value, Small-Cap Value, Growth, and Small-Cap Growth Index Funds employ
this method of indexing.

   Because it would be very expensive to buy and sell all of the stocks held in
certain indexes (the Wilshire 5000 Index, for example, includes more than 7,200
stocks), funds tracking these larger indexes use a "sampling" technique. Using a
sophisticated computer program, these funds select a representative sample of
stocks from their target index that will resemble the full index in terms of
industry weightings, market capitalization, price/earnings ratio, dividend
yield, and other characteristics. For instance, if 10% of the Wilshire 5000
Index were made up of utility stocks, the Total Stock Market Index Fund would
invest about 10% of its assets in some --  but not all -- of those utility
stocks. The particular utility stocks selected by the Fund, as a group, would
have investment characteristics similar to those of the utility stocks in the
Index. The Total Stock Market, Extended Market, and Small-Cap Index Funds employ
this method of indexing.

   The following table shows the number of stocks held by each of the Funds as
of December 31, 1998.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
      FUND            NUMBER OF STOCKS HELD     NUMBER OF STOCKS IN TARGET INDEX
- --------------------------------------------------------------------------------
<S>                   <C>                       <C>
Total Stock Market
500
Extended Market
Mid-Cap
Small-Cap
Value
Small-Cap Value
Growth
Small-Cap Growth
- --------------------------------------------------------------------------------
</TABLE>


- --------------------------------------------------------------------------------
                                PLAIN TALK ABOUT
                          GROWTH FUNDS AND VALUE FUNDS

Growth investing and value investing are two styles employed by stock fund
managers. Growth funds generally focus on companies believed to have
above-average potential for growth in revenue and earnings. Reflecting the
market's high expectations for superior growth, the prices of such stocks are
typically above-average in relation to such measures as revenue, earnings, book
value, and dividends. Value funds generally emphasize companies from which the
market does not expect strong growth. The prices of value stocks typically are
below-average in comparison to such factors as earnings and book value, and
these stocks typically pay above-average dividend yields. Growth and value
stocks have, in the past, produced similar long-term returns, though each
category has periods when it outperforms the other. In general, growth funds
appeal to investors who will accept more volatility in hopes of a greater
increase in share price. Growth funds also may appeal to investors with taxable
accounts who want a higher proportion of returns to come as capital gains (which
may be taxed at lower rates than dividend income). Value funds, by contrast, are
appropriate for investors who want some dividend income and the potential for
capital gains, but are less tolerant of share-price fluctuations.
- --------------------------------------------------------------------------------
<PAGE>   67
                                                                              21


ADDITIONAL RISK INFORMATION

[FLAG GRAPHIC]   EACH FUND IS SUBJECT TO MARKET RISK, WHICH IS THE POSSIBILITY
                 THAT STOCK PRICES OVERALL WILL DECLINE OVER SHORT OR EVEN LONG
                 PERIODS. STOCK MARKETS TEND TO MOVE IN CYCLES, WITH PERIODS OF
                 RISING STOCK PRICES AND PERIODS OF FALLING STOCK PRICES.

   To illustrate the volatility of stock prices, the following table shows the
best, worst, and average total returns for the U.S. stock market over various
periods as measured by the S&P 500 Index, which -- in addition to being the
target index for Vanguard 500 Index Fund -- is a widely used barometer of stock
market activity. (Total returns consist of dividend income plus change in market
price.) Note that the returns shown do not include the costs of buying and
selling stocks or other expenses that a real-world investment portfolio would
incur. Note, also, that the gap between best and worst tends to narrow over the
long term.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                            U.S. STOCK MARKET RETURNS (1926 - 1998)
- --------------------------------------------------------------------------------
                   1 YEAR           5 YEARS          10 YEARS         20 YEARS
- --------------------------------------------------------------------------------
<S>               <C>              <C>              <C>              <C>
Best                 54.2%            24.1%            19.9%            17.7%
Worst              - 43.1           - 12.4           - 0.8               3.1
Average              13.1             10.7             11.0             11.0
</TABLE>


- --------------------------------------------------------------------------------
                               PLAIN TALK ABOUT
                   LARGE-CAP, MID-CAP, AND SMALL-CAP STOCKS

Stocks of publicly traded companies -- and mutual funds that hold these stocks
- -- can be classified by the companies' market value, or capitalization.
Generally, Vanguard defines large-capitalization (large-cap) funds as those
holding stocks of companies whose outstanding shares have a market value
exceeding $10 billion. Mid-cap funds hold stocks of companies with a market
value between $1 billion and $10 billion. Small-cap funds typically hold stocks
of companies with a market value of less than $1 billion.
- --------------------------------------------------------------------------------

   The table covers all of the 1-, 5-, 10-, and 20-year periods from 1926
through 1998. You can see, for example, that while the average return on stocks
for all of the 5-year periods was 10.7%, returns for individual 5-year periods
ranged from a - 12.4% average (from 1928 through 1932) to 24.1% (from 1994
through 1998). These average returns reflect past performance on common stocks;
you should not regard them as an indication of future returns from either the
stock market as a whole or any Fund in particular.

   Keep in mind that the S&P 500 Index tracks mainly large-capitalization
stocks. Historically, the mid- and small-cap stocks of the Wilshire 4500, S&P
MidCap 400, and Russell 2000 Indexes (the target indexes for the Extended
Market, Mid-Cap, and Small-Cap Index Funds, respectively) have been more
volatile than -- and at times have performed quite differently from -- the
large-cap stocks of the S&P 500 Index.

   Even indexes that are subsets of the S&P 500 Index -- such as the S&P/BARRA
Value Index and the S&P/BARRA Growth Index (the target indexes for the Value and
Growth Index Funds) -- will not perform in the same way as the broader S&P 500
Index. Historically, stocks of the S&P/BARRA Value Index have been less volatile
than the stocks found in the broader S&P 500 Index; stocks of the S&P/BARRA
Growth Index, on the other hand, have displayed somewhat greater short-term
volatility than the S&P 500 Index's stocks. Historical performance aside,
however, both value and growth stocks have the potential at times to be more
volatile than the broader market.

[FLAG GRAPHIC]   THE FUNDS ARE ALSO SUBJECT, IN VARYING DEGREES, TO INVESTMENT
                 STYLE RISK, WHICH IS THE POSSIBILITY THAT RETURNS FROM A
                 SPECIFIC TYPE OF STOCK (FOR INSTANCE, SMALL-CAP OR VALUE) WILL
                 TRAIL RETURNS FROM OTHER ASSET CLASSES OR THE OVERALL STOCK
                 MARKET. EACH TYPE OF STOCK TENDS TO GO THROUGH CYCLES OF DOING
                 BETTER -- OR WORSE -- THAN COMMON STOCKS IN GENERAL. THESE
                 PERIODS HAVE, IN THE PAST, LASTED FOR AS LONG AS SEVERAL YEARS.

TRANSACTION FEES AND ACCOUNT MAINTENANCE

Some of Vanguard's index funds charge a transaction fee on purchases of fund
shares to offset the higher costs of trading certain securities, particularly
small-company stocks. The transaction fee ensures that these higher costs are
<PAGE>   68
22


borne by the investors making the transactions -- and not by shareholders
already in the fund. Without transaction fees, an index fund would have trouble
tracking its target index.

   In addition, most of Vanguard's index funds charge an account maintenance fee
on accounts under $10,000 to divide the costs of maintaining accounts equitably
among shareholders.

   At Vanguard, fees are paid directly into the fund itself (unlike the sales
charge or load imposed by many fund companies, which ends up in the pocket of
the sponsor, adviser, or sales representative).

COSTS AND MARKET-TIMING

Some investors try to profit from a strategy called market-timing --switching
money into investments when they expect prices to rise, and taking money out
when they expect prices to fall. As money is shifted in and out, a fund incurs
expenses for buying and selling securities. These costs are borne by all fund
shareholders, including the long-term investors who do not generate the costs.
Therefore, the Funds have adopted the following policies, among others, designed
to discourage short-term trading:

- -  Each Fund reserves the right to reject any purchase request -- including
   exchanges from other Vanguard funds -- that it regards as disruptive to the
   efficient management of the Fund. This could be because of the timing of the
   investment or because of a history of excessive trading by the investor.

- -  Five of the Funds (Extended Market, Mid-Cap, Small-Cap, Small-Cap Value, and
   Small-Cap Growth) charge a transaction fee on purchases.

- -  There is a limit on the number of times you can exchange into and out of a
   Fund (see "Exchanges" in the INVESTING WITH VANGUARD section).

- -  Telephone and online exchanges are not permitted for non-IRA accounts.

   The Vanguard funds do not permit market-timing. Do not invest in these Funds
if you are a market-timer.

- --------------------------------------------------------------------------------
                                PLAIN TALK ABOUT
                                  TURNOVER RATE

Before investing in a mutual fund, you should review its turnover rate. This
gives an indication of how transaction costs could affect the fund's future
returns. In general, the greater the volume of buying and selling by the fund,
the greater the impact that brokerage commissions and other transaction costs
will have on its return. Also, funds with high turnover rates may be more likely
to generate capital gains that must be distributed to shareholders as income
subject to taxes. The average turnover rate for passively managed domestic
equity index funds investing in common stocks is roughly -%; for all domestic
stock funds, the average turnover rate is approximately -%, according to
Morningstar, Inc.
- --------------------------------------------------------------------------------

TURNOVER RATE

Although each Fund seeks to invest for the long term, the Funds retain the right
to sell securities regardless of how long the securities have been held.
Generally, a passively managed fund sells securities only to respond to
redemption requests or to adjust the number of shares held to reflect a change
in the fund's target index. Because of this, the turnover rate for the Funds has
been extremely low, with averages over the past five years (or since inception)
ranging from 2% for the Total Stock Market Index Fund to 29% for the Small-Cap
Index Fund. (A turnover rate of 100% would occur, for example, if a Fund sold
and replaced securities valued at 100% of its net assets within a one-year
period.) The turnover rate of each Fund for each of the last five years (or the
life of the Fund, if shorter) is shown in the FINANCIAL HIGHLIGHTS section of
this prospectus.

INVESTMENT POLICIES

Each Fund reserves the right to substitute a different index for the index it
currently tracks if the current index is discontinued or for any other reason
determined in good faith by the Fund's Board of Trustees. In every such
instance, the substitute index will measure the same general market (large-,
mid-, or small-cap, growth, or value) as the current index.

   Each Fund may invest in foreign securities to the extent necessary to carry
out its investment strategy of holding all, or a representative sample, of the
stocks that comprise the index it tracks. It is not expected that any Fund will
invest more than 5% of its assets in foreign securities.
<PAGE>   69
                                                                              23


   Although index funds, by their nature, tend to be tax-efficient investment
vehicles, the Funds generally are managed without regard to tax ramifications.

   To track their target indexes as closely as possible, the Funds attempt to
remain fully invested in stocks. To help stay fully invested, and to reduce
transaction costs, the Funds may invest, to a limited extent, in stock futures
and options contracts, warrants, convertible securities, and swap agreements,
which are types of derivatives.

   Losses (or gains) involving futures can sometimes be substantial -- in part
because a relatively small price movement in a futures may result in an
immediate and substantial loss (or gain) for a fund. Similar risks exist for
warrants (securities that permit their owners to purchase a specific number of
stock shares at a predetermined price), convertible securities (securities that
may be exchanged for another asset), and swap agreements (contracts in which
each party agrees to make payments to the other based on the return of a
specified index or asset).

   For this reason, the Funds will not use futures, options, warrants,
convertible securities, or swap agreements for speculative purposes or as
leveraged investments that magnify the gains or losses of an investment. The
value of all futures contracts in which any Fund acquires an interest cannot
exceed 20% of that Fund's total assets.

   The reasons for which a Fund will invest in futures and options are:

- -  To keep cash on hand to meet shareholder redemptions or other needs while
   simulating full investment in stocks.

- -  To reduce the Fund's transaction costs or add value when these instruments
   are favorably priced.

- --------------------------------------------------------------------------------
                                PLAIN TALK ABOUT
                    VANGUARD'S UNIQUE CORPORATE STRUCTURE

The Vanguard Group is truly a MUTUAL mutual fund company. It is owned jointly by
the funds it oversees and thus indirectly by the shareholders in those funds.
Most other mutual funds are operated by for-profit management companies that may
be owned by one person, by a group of individuals, or by investors who own the
management company's stock. By contrast, Vanguard provides its services on an
"at-cost" basis, and the funds' expense ratios reflect only these costs. No
separate management company reaps profits or absorbs losses from operating the
funds.
- --------------------------------------------------------------------------------

THE FUNDS AND VANGUARD

The Funds are members of The Vanguard Group, a family of more than 35 investment
companies with more than 100 distinct investment portfolios holding assets worth
more than $- billion. All of the funds share in the expenses associated with
business operations, such as personnel, office space, equipment, and
advertising.

   Vanguard also provides marketing services to the funds. Although shareholders
do not pay sales commissions or 12b-1 distribution fees, each fund pays its
allocated share of The Vanguard Group's marketing costs.

INVESTMENT ADVISER

Vanguard Core Management Group (the "Group"), P.O. Box 2600, Valley Forge, PA
19482, provides advisory services on an at-cost basis to the Vanguard U.S. Stock
Index Funds. For the fiscal year ended December 31, 1998, the Funds paid
advisory fees at an effective annual rate (applied to the average daily net
assets of each Fund) of -% for the Total Stock Market Index Fund; -% for the 500
Index Fund; -% for the Extended Market Index Fund; -% for the Small-Cap Index
Fund; -% for the Value Index Fund; and -% for the Growth Index Fund. As of the
date of this prospectus, the Mid-Cap, Small-Cap Value, and Small-Cap Growth
Index Funds had not operated for a full fiscal year; if they had, it is
estimated that they would have paid advisory fees (applied to average daily net
assets) of -%, -%, and -%, respectively.

   The Funds have authorized the Group to choose brokers or dealers to handle
the purchase and sale of securities for the Funds, and to get the best available
price and most favorable execution from these brokers with respect to all
transactions. The Funds may direct the Group to use a particular broker for
certain transactions in exchange for commission rebates or research services
provided to the Funds.
<PAGE>   70
24


- --------------------------------------------------------------------------------
                                PLAIN TALK ABOUT
                               THE FUNDS' ADVISER

Vanguard Core Management Group provides investment advisory services to many
Vanguard funds. As of December 31, 1998, the Group managed more than $___
billion in total assets. The individual responsible for overseeing each Fund's
investments is:

   GEORGE U. SAUTER, Managing Director of Vanguard; has worked in investment
management since 1985; has managed portfolio investments since 19__; with
Vanguard since 1987; A.B., Dartmouth College; M.B.A., University of Chicago.
- --------------------------------------------------------------------------------

YEAR 2000 CHALLENGE

The common practice in computer programming of using just two digits to identify
a year has resulted in the Year 2000 challenge throughout the information
technology industry. If unchanged, many computer applications and systems could
misinterpret dates occurring after December 31, 1999, leading to errors or
failure. Such failure could adversely affect a fund's operations, including
pricing, securities trading, and the servicing of shareholder accounts.

   The Vanguard Group is dedicated to providing uninterrupted, high-quality
performance from our computer systems before, during, and after 2000. In July
1998, we completed the renovation and initial testing of our internal systems.
Vanguard is diligently working with external partners, suppliers, and vendors,
including fund managers and other service providers, to assure that the systems
with which we interact remain operational at all times.

   In addition to taking every reasonable step to secure our internal systems
and external relationships, Vanguard is further developing contingency plans
intended to assure that unexpected systems failures will not adversely affect
the Funds' operations. Vanguard intends to monitor these processes through the
rollover of 1999 into 2000 and to quickly implement alternate solutions if
necessary.

   However, despite Vanguard's efforts and contingency plans, noncompliant
computer systems could have a material adverse effect on a Fund's business,
operations, or financial condition. Additionally, a Fund's performance could be
hurt if a computer-system failure at a company or governmental unit affects the
price of securities the Fund owns.


DIVIDENDS, CAPITAL GAINS, AND TAXES

The Funds distribute to shareholders virtually all of their net income (interest
and dividends less expenses) as well as any capital gains realized from the sale
of their holdings. Income distributions for the Total Stock Market, 500, Value,
and Growth Index Funds generally occur in March, June, September, and December;
income distributions for the Extended Market, Mid-Cap, Small-Cap, Small-Cap
Value, and Small-Cap Growth Index Funds generally occur in December. Capital
gains distributions for all nine Funds generally occur in December. In addition,
the Funds may occasionally be required to make supplemental dividend or capital
gains distributions at some other time during the year. Keep in mind that index
funds tend to provide less in capital gains distributions than actively managed
funds generally do.


- --------------------------------------------------------------------------------
                                PLAIN TALK ABOUT
                                  DISTRIBUTIONS

As a shareholder, you are entitled to your share of the fund's income from
interest and dividends, and gains from the sale of investments. You receive such
earnings as either an income dividend or a capital gains distribution. Income
dividends come from both the dividends that the fund earns from its holdings and
the interest it receives from its money market and bond investments. Capital
gains are realized whenever the fund sells securities for higher prices than it
paid for them. The capital gains are either short-term or long-term depending on
whether the fund held the securities for less than or more than one year.
- --------------------------------------------------------------------------------
<PAGE>   71
                                                                              25


   Dividend and capital gains distributions of Fund shares held as an investment
option in an employer-sponsored retirement or savings plan will be reinvested in
additional Fund shares and accumulate on a tax-deferred basis. You will not owe
taxes on these distributions until you begin withdrawals. You should consult
your plan administrator, your plan's Summary Plan Description, or your own tax
adviser about the tax consequences of an investment in any of the Funds and of
any plan withdrawals.


SHARE PRICE

Each Fund's share price, called its net asset value, or NAV, is calculated each
business day after the close of trading on the New York Stock Exchange (the NAV
is not calculated on holidays or other days the Exchange is closed). Net asset
value per share is computed by adding up the total value of the Fund's
investments and other assets, subtracting any of its liabilities (debts), and
then dividing by the number of Fund shares outstanding:

                                     TOTAL ASSETS   -   LIABILITIES
           NET ASSET VALUE    = -----------------------------------------
                                      NUMBER OF SHARES OUTSTANDING

  Knowing the daily net asset value is useful to you as a shareholder because it
indicates the current value of your investment. The Fund's NAV, multiplied by
the number of shares you own, gives you the dollar amount you would have
received had you sold all of your shares back to the Fund that day.

   A NOTE ON PRICING: A Fund's investments will be priced at their market value
when market quotations are readily available. When these quotations are not
readily available, investments will be priced at their fair value, calculated
according to procedures adopted by the Funds' Board of Trustees.

   Each Fund's share price can be found daily in the mutual fund listings of
most major newspapers under the heading "Vanguard Index Funds." Different
newspapers use different abbreviations for each Fund, but the most common are
TOTST, 500, EXTND, MIDCP, SMCAP, VALUE, SMVAL, GROWTH, and SMGTH.
<PAGE>   72
26


- --------------------------------------------------------------------------------
                                PLAIN TALK ABOUT
                  HOW TO READ THE FINANCIAL HIGHLIGHTS TABLE

This explanation uses the Total Stock Market Index Fund as an example. The Fund
began fiscal 1998 with a net asset value (price) of $ - per share. During the
year, the Fund earned $ - per share from investment income (interest and
dividends) and $ - per share from investments that had appreciated in value or
that were sold for higher prices than the Fund paid for them.

   Shareholders received $ - per share in the form of dividend and capital gains
distributions. A portion of each year's distributions may come from the prior
year's income or capital gains.

   The earnings ($ - per share) minus the distributions ($ - per share) resulted
in a share price of $ - at the end of the year. This was an increase of $ - per
share (from $ - at the beginning of the year to $ - at the end of the year). For
a shareholder who reinvested the distributions in the purchase of more shares,
the total return from the Fund was - % for the year.

   As of December 31, 1998, the Fund had $ - billion in net assets. For the
year, its expense ratio was - % ($ - per $1,000 of net assets); and its net
investment income amounted to - % of its average net assets. It sold and
replaced securities valued at - % of its net assets.
- --------------------------------------------------------------------------------


FINANCIAL HIGHLIGHTS

The following financial highlights tables are intended to help you understand
each Fund's financial performance for the past five years*, and certain
information reflects financial results for a single Fund share in each case. The
total returns in each table represent the rate that an investor would have
earned or lost each year on an investment in the Fund (assuming reinvestment of
all dividends and distributions). This information has been derived from the
financial statements audited by PricewaterhouseCoopers LLP, independent
accountants, whose report -- along with each Fund's financial statements -- is
included in the Trust's most recent annual report to shareholders. You may have
the annual report sent to you without charge by contacting Vanguard.

*  Because the Mid-Cap, Small-Cap Value, and Small-Cap Growth Index Funds did
   not begin operations until May 21, 1998, tables are not included for these
   Funds.

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------------
                                                                            VANGUARD TOTAL STOCK MARKET
                                                                                   INDEX FUND
                                                                                YEAR ENDED DECEMBER 31,
                                                      -----------------------------------------------------------------------------
                                                       1998          1997              1996              1995              1994
- -----------------------------------------------------------------------------------------------------------------------------------
<S>                                                   <C>         <C>               <C>               <C>               <C>
NET ASSET VALUE, BEGINNING OF YEAR                       -        $   17.77         $   15.04         $   11.37         $   11.69
- -----------------------------------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
 Net Investment Income                                   -             .319               .29               .29               .27
 Net Realized and Unrealized
  Gain (Loss) on Investments                             -            5.143              2.84              3.75              (.29)
                                                      -----------------------------------------------------------------------------
  Total from Investment Operations                       -            5.462              3.13              4.04              (.02)
                                                      -----------------------------------------------------------------------------
DISTRIBUTIONS
 Dividends from Net Investment Income                    -            (.322)             (.29)             (.28)             (.27)
 Distributions from Realized Capital Gains               -            (.270)             (.11)             (.09)             (.03)
                                                      -----------------------------------------------------------------------------
  Total Distributions                                    -            (.592)             (.40)             (.37)             (.30)
- -----------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                             -        $   22.64         $   17.77         $   15.04         $   11.37
===================================================================================================================================

TOTAL RETURN*                                            -            30.99%            20.96%            35.79%           - 0.17%
===================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
 Net Assets, End of Year (Millions)                      -        $   5,092         $   3,531         $   1,571         $     786
 Ratio of Total Expenses to
  Average Net Assets                                     -             0.20%             0.22%             0.25%             0.20%
 Ratio of Net Investment Income
  to Average Net Assets                                  -             1.65%             1.86%             2.14%             2.35%
 Turnover Rate                                           -                2%                3%                3%                2%
- -----------------------------------------------------------------------------------------------------------------------------------
</TABLE>

*  Total return figures do not reflect the 0.25% transaction fee on purchases
   through 1995 or the annual account maintenance fee of $10.

   From time to time, the Vanguard funds advertise yield and total return
figures. Yield is a measure of past dividend income. Total return includes both
past dividend income (assuming that it has been reinvested) plus realized and
unrealized capital appreciation (or depreciation). Neither yield nor total
return should be used to predict the future performance of a fund.
<PAGE>   73
                                                                              27

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------------
                                                                                VANGUARD 500 INDEX FUND
                                                                                  YEAR ENDED DECEMBER 31,
                                                         --------------------------------------------------------------------------
                                                              1998        1997          1996             1995             1994
- -----------------------------------------------------------------------------------------------------------------------------------
<S>                                                      <C>          <C>             <C>             <C>             <C>
NET ASSET VALUE, BEGINNING OF YEAR                              -     $   69.17       $   57.60       $   42.97       $    43.83
- -----------------------------------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
 Net Investment Income                                          -          1.31            1.28            1.22             1.18
 Net Realized and Unrealized Gain (Loss) on Investments         -         21.50           11.82           14.76             (.67)
                                                         --------------------------------------------------------------------------
  Total from Investment Operations                              -         22.81           13.10           15.98              .51
                                                         --------------------------------------------------------------------------
DISTRIBUTIONS
 Dividends from Net Investment Income                           -         (1.32)          (1.28)          (1.22)           (1.17)
 Distributions from Realized Capital Gains                      -          (.59)           (.25)           (.13)            (.20)
                                                         --------------------------------------------------------------------------
  Total Distributions                                           -         (1.91)          (1.53)          (1.35)           (1.37)
- -----------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                                    -     $   90.07       $   69.17       $   57.60       $    42.97
===================================================================================================================================

TOTAL RETURN*                                                   -         33.19%          22.88%          37.45%            1.18%
===================================================================================================================================

RATIOS/SUPPLEMENTAL DATA
 Net Assets, End of Year (Millions)                             -     $  49,358       $  30,332       $  17,372       $    9,356
 Ratio of Total Expenses to Average Net Assets                  -          0.19%           0.20%           0.20%            0.19%
 Ratio of Net Investment Income to Average Net Assets           -          1.66%           2.04%           2.38%            2.72%
 Turnover Rate**                                                -             5%              5%              4%               6%
- -----------------------------------------------------------------------------------------------------------------------------------
</TABLE>


*  Total return figures do not reflect the annual account maintenance fee of
   $10.

** Turnover rates excluding in-kind redemptions were 1%, 3%, 2%, 2%, 4%, and 2%,
   respectively.

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------------
                                                                                   VANGUARD EXTENDED MARKET INDEX FUND
                                                                                        YEAR ENDED DECEMBER 31,
                                                              ---------------------------------------------------------------------
                                                                      1998      1997            1996           1995          1994
- -----------------------------------------------------------------------------------------------------------------------------------
<S>                                                                 <C>       <C>              <C>           <C>           <C>
NET ASSET VALUE, BEGINNING OF YEAR                                      -     $  26.20         $ 24.07       $ 18.52       $ 19.43
- -----------------------------------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
    Net Investment Income                                               -         .351             .34           .30           .28
    Net Realized and Unrealized Gain (Loss) on Investments              -        6.479            3.85          5.95          (.62)
                                                              ---------------------------------------------------------------------
       Total from Investment Operations                                 -        6.830            4.19          6.25          (.34)
                                                              ---------------------------------------------------------------------
DISTRIBUTIONS
    Dividends from Net Investment Income                                -        (.360)           (.34)         (.30)         (.28)
    Distributions from Realized Capital Gains                           -       (1.910)          (1.72)         (.40)         (.29)
                                                              ---------------------------------------------------------------------
       Total Distributions                                              -       (2.270)          (2.06)         (.70)         (.57)
- -----------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                                            -     $  30.76         $ 26.20       $ 24.07       $ 18.52
===================================================================================================================================

TOTAL RETURN*                                                           -        26.73%          17.65%        33.80%       - 1.76%
===================================================================================================================================

RATIOS/SUPPLEMENTAL DATA
  Net Assets, End of Year (Millions)                                    -     $  2,723         $ 2,099       $ 1,523       $   967
  Ratio of Total Expenses to Average Net Assets                         -         0.23%           0.25%         0.25%         0.20%
  Ratio of Net Investment Income to Average Net Assets                  -         1.30%           1.42%         1.51%         1.51%
  Turnover Rate                                                         -           15%**           22%           15%           19%
- -----------------------------------------------------------------------------------------------------------------------------------
</TABLE>


*  Total return figures do not reflect transaction fees on purchases (0.25%
   after October 31, 1997; 0.5% in 1995 through October 31, 1997; 1.0% in 1993
   through 1994) or the annual account maintenance fee of $10.

** Turnover rate excluding in-kind redemptions was 14%.
<PAGE>   74
28


<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------------
                                                                            VANGUARD SMALL-CAP INDEX FUND
                                                 YEAR ENDED DECEMBER 31,
                                         ---------------------------------------    FEB. 1* TO     OCT. 1, 1993, TO     YEAR ENDED
                                           1998     1997        1996       1995    DEC. 31, 1994     JAN. 31, 1994    SEP. 30, 1993
- -----------------------------------------------------------------------------------------------------------------------------------
<S>                                      <C>      <C>         <C>        <C>       <C>             <C>                <C>
NET ASSET VALUE, BEGINNING OF PERIOD        -     $ 20.23     $ 18.61    $ 14.99      $  16.24           $ 16.23          $  12.63
INVESTMENT OPERATIONS
    Net Investment Income                   -        .277         .26        .24           .20               .05               .20
    Net Realized and Unrealized
       Gain (Loss) on Investments           -       4.632        3.07       4.06          (.86)              .96              3.73
                                         ------------------------------------------------------------------------------------------
       Total from Investment
       Operations                           -       4.909        3.33       4.30          (.66)             1.01              3.93
                                         ------------------------------------------------------------------------------------------
DISTRIBUTIONS
    Dividends from Net
       Investment Income                    -       (.274)       (.27)      (.23)         (.22)             (.18)             (.18)
    Distributions from Realized
       Capital Gains                        -      (1.115)      (1.44)      (.45)         (.37)             (.82)             (.15)
                                         ------------------------------------------------------------------------------------------
       Total Distributions                  -      (1.389)      (1.71)      (.68)         (.59)            (1.00)             (.33)
- -----------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD              -     $ 23.75     $ 20.23    $ 18.61      $  14.99           $ 16.24          $  16.23
===================================================================================================================================

TOTAL RETURN**                              -       24.59%      18.12%     28.74%       - 4.00              6.65%            31.60%
===================================================================================================================================

RATIOS/SUPPLEMENTAL DATA
    Net Assets, End of Period (Millions)    -     $ 2,652     $ 1,713    $   971      $    605           $   533          $    432
    Ratio of Total Expenses to
       Average Net Assets                   -        0.23%       0.25%      0.25%         0.17%+            0.18%+            0.18%
    Ratio of Net Investment Income to
       Average Net Assets                   -        1.38%       1.51%      1.58%         1.50%+            1.16%+            1.47%
    Turnover Rate                           -          29%         28%        28%           25%                5%               26%
- -----------------------------------------------------------------------------------------------------------------------------------
</TABLE>

*  Date of reorganization of Vanguard Small Capitalization Stock Fund into
   Vanguard Index Trust - Small Capitalization Stock Portfolio.

** Total return figures do not reflect transaction fees on purchases (0.5% after
   1996, 1.0% in 1993 through 1996) or the annual account maintenance fee of
   $10.

+  Annualized.


<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------------
                                                                                 VANGUARD VALUE INDEX FUND
                                                                                  YEAR ENDED DECEMBER 31,
                                                            -----------------------------------------------------------------------
                                                               1998         1997             1996            1995          1994
- -----------------------------------------------------------------------------------------------------------------------------------
<S>                                                         <C>           <C>             <C>             <C>             <C>
NET ASSET VALUE, BEGINNING OF YEAR                               --       $   17.02       $   14.79       $   11.12       $   11.74
- -----------------------------------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
  Net Investment Income                                          -              .38             .37             .41             .38
  Net Realized and Unrealized Gain (Loss) on Investments         -             4.57            2.81            3.66            (.46)
                                                            -----------------------------------------------------------------------
   Total from Investment Operations                              -             4.95            3.18            4.07            (.08)
                                                            -----------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income                           -             (.37)           (.38)           (.40)           (.38)
  Distributions from Realized Capital Gains                      -             (.75)           (.57)             --            (.16)
                                                            -----------------------------------------------------------------------
   Total Distributions                                           -            (1.12)           (.95)           (.40)           (.54)
- -----------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                                     -        $   20.85       $   17.02       $   14.79       $   11.12
===================================================================================================================================
TOTAL RETURN*                                                    -            29.77%          21.86%          36.94%         - 0.73%
===================================================================================================================================

RATIOS/SUPPLEMENTAL DATA
  Net Assets, End of Year (Millions)                             -        $   1,796       $   1,016       $     496       $     297
  Ratio of Total Expenses to Average Net Assets                  -             0.20%           0.20%           0.20%           0.20%
  Ratio of Net Investment Income to Average Net Assets           -             2.05%           2.54%           3.06%           3.37%
  Turnover Rate                                                  -               25%             29%             27%             32%
- -----------------------------------------------------------------------------------------------------------------------------------
</TABLE>

*Total return figures do not reflect the annual account maintenance fee of $10.
<PAGE>   75
29


<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------------
                                                                                  VANGUARD GROWTH INDEX FUND
                                                                                    YEAR ENDED DECEMBER 31,
                                                            -----------------------------------------------------------------------
                                                               1998          1997            1996            1995            1994
- -----------------------------------------------------------------------------------------------------------------------------------
<S>                                                         <C>           <C>            <C>             <C>             <C>
NET ASSET VALUE, BEGINNING OF YEAR                                -       $  16.90       $   13.97       $   10.28       $   10.20
- -----------------------------------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
  Net Investment Income                                           -            .23             .22             .21             .21
  Net Realized and Unrealized Gain (Loss) on Investments          -           5.88            3.07            3.68             .08
                                                            -----------------------------------------------------------------------
   Total from Investment Operations                               -           6.11            3.29            3.89             .29
                                                            -----------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income                            -           (.23)           (.22)           (.20)           (.21)
  Distributions from Realized Capital Gains                       -           (.25)           (.14)             --              --
                                                            -----------------------------------------------------------------------
   Total Distributions                                            -           (.48)           (.36)           (.20)           (.21)
- -----------------------------------------------------------------------------------------------------------------------------------

NET ASSET VALUE, END OF YEAR                                      -       $  22.53       $   16.90       $   13.97       $   10.28
===================================================================================================================================

TOTAL RETURN*                                                     -          36.34%          23.74%          38.06%           2.89%
===================================================================================================================================

RATIOS/SUPPLEMENTAL DATA
  Net Assets, End of Year (Millions)                              -       $  2,365       $     787       $     271       $      86
  Ratio of Total Expenses to Average Net Assets                   -           0.20%           0.20%           0.20%           0.20%
  Ratio of Net Investment Income to Average Net Assets            -           1.19%           1.57%           1.71%           2.08%
  Turnover Rate                                                   -             26%             29%             24%             28%
- -----------------------------------------------------------------------------------------------------------------------------------
</TABLE>


*  Total return figures do not reflect the annual account maintenance fee of
   $10.


"Standard & Poor's(R)," "S&P(R)," "S&P 500(R)," "Standard & Poor's 500," "500,"
"S&P MidCap 400," and "S&P SmallCap 600" are trademarks of The McGraw-Hill
Companies, Inc., and have been licensed for use by Vanguard U.S. Stock Index
Funds and The Vanguard Group. These mutual funds are not sponsored, endorsed,
sold, or promoted by Standard & Poor's, and Standard & Poor's makes no
representation regarding the advisability of investing in the Funds. "Wilshire
4500" and "Wilshire 5000" are registered trademarks of Wilshire Associates.
Frank Russell Company is the owner of the trademarks and copyrights relating to
the Russell Indexes.
<PAGE>   76
30

INVESTING WITH VANGUARD

One or more of the Funds is an investment option in your retirement or savings
plan. Your plan administrator or your employee benefits office can provide you
with detailed information on how to participate in your plan and how to elect a
Fund as an investment option.

- -  If you have any questions about a Fund or Vanguard, including the Fund's
   investment objective, strategies, or risks, contact Vanguard's Participant
   Services Center, toll-free, at 1-800-523-1188.

- -  If you have questions about your account, contact your plan administrator or
   the organization that provides recordkeeping services for your plan.

INVESTMENT OPTIONS AND ALLOCATIONS

Your plan's specific provisions may allow you to change your investment
selections, the amount of your contributions, or how your contributions are
allocated among the investment choices available to you. Contact your plan
administrator or employee benefits office for more details.

TRANSACTIONS

Contributions, exchanges, or redemptions of a Fund's shares are processed as
soon as they have been received by Vanguard in good order. Good order means that
your request includes complete information on your contribution, exchange, or
redemption, and that Vanguard has received the appropriate assets.

EXCHANGES

The exchange privilege (your ability to redeem shares from one fund to purchase
shares of another fund) may be available to you through your plan. Although we
make every effort to maintain the exchange privilege, Vanguard reserves the
right to revise or terminate this privilege, limit the amount of an exchange or
reject any exchange, at any time, without notice. Because excessive exchanges
can potentially disrupt the management of a Fund and increase its transaction
costs, Vanguard limits participant exchange activity to no more than FOUR
SUBSTANTIVE "ROUND TRIPS" THROUGH THE FUND (at least 90 days apart) during any
12-month period. A "round trip" is a redemption from the Fund followed by a
purchase back into the Fund. "Substantive" means a dollar amount that Vanguard
determines, in its sole discretion, could adversely affect the management of the
Fund.

  Before making an exchange to or from another fund available in your plan,
consider the following:

- -  Certain investment options, particularly funds made up of company stock or
   investment contracts, may be subject to unique restrictions.

- -  Make sure to read that fund's prospectus. Contact Participant Services,
   toll-free, at 1-800-523-1188 for a copy.

- -  Vanguard can accept exchanges only as permitted by your plan. Contact your
   plan administrator for details on the exchange policies that apply to your
   plan.


ACCESSING FUND INFORMATION BY COMPUTER

- --------------------------------------------------------------------------------
VANGUARD ON THE WORLD WIDE WEB www.vanguard.com

Use your personal computer to visit Vanguard's education-oriented website, which
provides timely news and information about Vanguard funds and services; an
online "university" that offers a variety of mutual fund classes; and
easy-to-use, interactive tools to help you create your own investment and
retirement strategies.
- --------------------------------------------------------------------------------
<PAGE>   77
                    (This page intentionally left blank.)
<PAGE>   78
                    (This page intentionally left blank.)


<PAGE>   79
GLOSSARY OF INVESTMENT TERMS

ACTIVE MANAGEMENT

An investment approach that seeks to exceed the average returns of the financial
markets. Active managers rely on research, market forecasts, and their own
judgment and experience in selecting securities to buy and sell.

CAPITAL GAINS DISTRIBUTION

Payment to mutual fund shareholders of gains realized on securities that the
fund has sold at a profit, minus any realized losses.

CASH RESERVES

Cash deposits, short-term bank deposits, and money market instruments which
include U.S. Treasury bills, bank certificates of deposit (CDs), repurchase
agreements, commercial paper, and banker's acceptances.

COMMON STOCK

A security representing ownership rights in a corporation. A stockholder is
entitled to share in the company's profits, some of which may be paid out as
dividends.

DIVIDEND INCOME

Payment to shareholders of income from interest or dividends generated by a
fund's investments.

DOLLAR-COST AVERAGING

Investing equal amounts of money at regular intervals on an ongoing basis. This
technique ensures that an investor buys fewer shares when prices are high and
more shares when prices are low.

EXPENSE RATIO

The percentage of a fund's average net assets used to pay its expenses. The
expense ratio includes management fees, administrative fees, and any 12b-1
marketing fees.

INDEX

An unmanaged group of securities whose overall performance is used as a standard
to measure investment performance.

INVESTMENT ADVISER

An organization that makes the day-to-day decisions regarding a fund's
investments.

MUTUAL FUND

An investment company that pools the money of many people and invests it in a
variety of securities in an effort to achieve a specific objective over time.

NET ASSET VALUE (NAV)

The market value of a mutual fund's total assets, minus liabilities, divided by
the number of shares outstanding. The value of a single share is called its
share value or share price.

PASSIVE MANAGEMENT

A low-cost investment strategy in which a mutual fund attempts to match --
rather than outperform -- a particular stock or bond market index. Also known as
indexing.

PRINCIPAL

The amount of your own money you put into an investment.

SECURITIES

Stocks, bonds, money market instruments, and other investment vehicles.

TOTAL RETURN

A percentage change, over a specified time period, in a mutual fund's net asset
value, with the ending net asset value adjusted to account for the reinvestment
of all distributions of dividends and capital gains.

VOLATILITY

The fluctuations in value of a mutual fund or other security. The greater a
fund's volatility, the wider the fluctuations between its high and low prices.

YIELD

Income (interest or dividends) earned by an investment, expressed as a
percentage of the investment's price.
<PAGE>   80
[THE VANGUARD GROUP LOGO]
Institutional Division
Post Office Box 2900
Valley Forge, PA 19482-2900


FOR MORE INFORMATION

If you'd like more information about Vanguard U.S. Stock Index Funds, the
following documents are available free upon request:

ANNUAL/SEMIANNUAL REPORT TO SHAREHOLDERS

Additional information about the Funds' investments is available in the Funds'
annual and semiannual reports to shareholders. In these reports, you will find a
discussion of the market conditions and investment strategies that significantly
affected the Funds' performance during the most recent fiscal year.

STATEMENT OF ADDITIONAL INFORMATION (SAI)

The SAI provides more detailed information about the Funds.

The current annual and semiannual reports and the SAI are incorporated by
reference into (and are thus legally a part of) this prospectus.

To receive a free copy of the latest annual or semiannual report or the SAI, or
to request additional information about the Funds or other Vanguard funds,
please contact us as follows:

THE VANGUARD GROUP
PARTICIPANT SERVICES CENTER
P.O. BOX 2900
VALLEY FORGE, PA 19482-2900

TELEPHONE:
1-800-523-1188

TEXT TELEPHONE:
1-800-523-8004

WORLD WIDE WEB:
www.vanguard.com

INFORMATION PROVIDED BY THE SECURITIES AND EXCHANGE COMMISSION (SEC)

You can review and copy information about the Funds (including the SAI) at the
SEC's Public Reference Room in Washington, D.C. To find out more about this
public service, call the SEC at 1-800-SEC-0330. Reports and other information
about the Funds are also available on the SEC's website (www.sec.gov), or you
can receive copies of this information, for a fee, by writing the Public
Reference Section, Securities and Exchange Commission, Washington, DC
20549-6009.

Funds' Investment Company Act file number: 811-2652

(C) 1999 The Vanguard Group, Inc.
All rights reserved.
Vanguard Marketing
Corporation, Distributor.

I040N - 04/26/1999
    
<PAGE>   81
   
VANGUARD INSTITUTIONAL INDEX FUND
VANGUARD U.S. STOCK INDEX FUNDS

Prospectus
April 26, 1999

CONTENTS

 1   AN INTRODUCTION TO INDEX FUNDS

     FUND PROFILES

 2   Vanguard Institutional Index Fund



     Institutional and Institutional Plus Shares

 5   Vanguard Total Stock Market



     Index Fund Institutional Shares

 7   Vanguard Extended Market



     Index Fund Institutional Shares

 9   Vanguard Mid-Cap Index Fund Institutional Shares

11   Vanguard Small-Cap Index Fund
     Institutional Shares

13   Vanguard Value Index Fund Institutional Shares

15   Vanguard Small-Cap Value Index Fund



     Institutional Shares

17   Vanguard Growth Index Fund Institutional Shares

19   Vanguard Small-Cap Growth



     Index Fund Institutional Shares

21   MORE ON THE FUNDS

24   THE FUNDS AND VANGUARD

24   INVESTMENT ADVISER

25   YEAR 2000 CHALLENGE

25   DIVIDENDS, CAPITAL GAINS, AND TAXES

26   SHARE PRICE

27   FINANCIAL HIGHLIGHTS

30   INVESTING WITH VANGUARD

30   SERVICES AND ACCOUNT FEATURES

30   TYPES OF ACCOUNTS

31   BUYING SHARES

32   REDEEMING SHARES

35   TRANSFERRING REGISTRATION

35   FUND AND ACCOUNT UPDATES

35   MANDATORY CONVERSION TO INVESTOR SHARES

GLOSSARY (inside back cover)


WHY READING THIS PROSPECTUS IS IMPORTANT

This prospectus explains the objective, risks, and strategies of certain
Vanguard index funds. To highlight terms and concepts important to mutual fund
investors, we have provided "Plain Talk(R)" explanations along the way. Reading
the prospectus will help you to decide which Funds, if any, are the right
investments for you. We suggest that you keep it for future reference.

OTHER CLASSES OF SHARES AND OTHER PROSPECTUSES

Vanguard currently offers nine U.S. stock index funds. Each of these funds,
other than Vanguard 500 Index Fund, issues two classes of shares: Institutional
Shares and Investor Shares. Institutional Shares are intended for persons that
are investing at least $10 million and that generally do not require special
employee benefit services. For those wishing to invest at least $10 million in
an S&P 500 index fund and who generally do not require special employee benefit
services, Vanguard offers the Vanguard Institutional Index Fund. This Fund
issues: Institutional Shares for those investing less than $200 million, and
Institutional Plus Shares for those investing $200 million or more.

   This prospectus describes the Institutional Shares offered by each of the
Vanguard U.S. Stock Index Funds (other than Vanguard 500 Index Fund, which does
not offer Institutional Shares) and the Institutional Shares and Institutional
Plus Shares offered by Vanguard Institutional Index Fund. If you are interested
in purchasing Investor Shares, please call Vanguard at 1-800-662-7447 (or
1-800-523-1036 if you will be purchasing through an employer-sponsored
retirement plan).

   Note that the Funds' separate share classes have different expenses; as a
result, their investment performance will vary.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.
<PAGE>   82
                                                                               1


   This prospectus provides information about Vanguard Institutional Index Fund
and the Vanguard U.S. Stock Index Funds that offer Institutional Shares. After
the introduction below, you'll find profiles that summarize key features of each
Fund. Following the profiles, there is important additional information common
to all of the Funds.

AN INTRODUCTION TO INDEX FUNDS

WHAT IS INDEXING?

An index is an unmanaged group of securities whose overall performance is used
as a standard to measure investment performance. An index (or "passively
managed") fund tries to match, as closely as possible, the performance of an
established target index. The fund does this by holding all, or a representative
sample, of the securities in the index.

   Index funds may seek to track indexes that hold a certain type of stock --
such as growth or value, small-cap or large-cap, or those from just one industry
- -- or they may seek to track indexes that consist of a broader range of stocks
- -- for example, the entire U.S. stock market.

   Index funds are not actively managed by investment advisers who buy and sell
securities based on research and analysis, in an attempt to outperform the
market as a whole. Rather, index funds simply mirror what the target index does,
for better or worse.

WHY INVEST IN INDEX FUNDS?

Index funds appeal to many investors for a number of reasons:

- -  Simplicity. Indexing is a straightforward market-matching strategy.

- -  Diversification. Indexes generally cover a wide variety of companies and
   industries.

- -  Relative performance predictability. An index fund is expected to closely
   parallel the performance of its target index.

- -  Low cost. Index funds do not have many of the expenses of an actively managed
   fund -- such as research -- and keep trading activity, and thus brokerage
   commissions, to a minimum.

- -  Low realization of capital gains. Because an index fund typically sells
   securities only to respond to redemption requests or to adjust the number of
   shares it holds to reflect a change in its target index, the fund's turnover
   rate -- and thus its realization of taxable capital gains -- is usually very
   low.

   KEEP IN MIND THAT AN INDEX FUND HAS OPERATING EXPENSES AND TRANSACTION COSTS;
A MARKET INDEX DOES NOT. THEREFORE, AN INDEX FUND -- WHILE EXPECTED TO TRACK ITS
TARGET INDEX AS CLOSELY AS POSSIBLE -- WILL TYPICALLY BE UNABLE TO MATCH THE
PERFORMANCE OF THE INDEX EXACTLY.

   For more information about index funds, see "Indexing Methods" under MORE ON
THE FUNDS.

                                PLAIN TALK ABOUT

                             THE COSTS OF INVESTING

Costs are an important consideration in choosing a mutual fund. That's because
you, as a shareholder, pay the costs of operating a fund, plus any transaction
costs associated with the fund's buying and selling of securities. These costs
can erode a substantial portion of the gross income or capital appreciation a
fund achieves. Even seemingly small differences in fund expenses can, over time,
have a dramatic effect on a fund's performance.
<PAGE>   83
2


FUND PROFILE -- VANGUARD INSTITUTIONAL INDEX FUND
INSTITUTIONAL AND INSTITUTIONAL PLUS SHARES

The following profile summarizes key features of Vanguard Institutional Index
Fund Institutional and Institutional Plus Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's 500 Composite Stock Price Index, which is dominated by
the stocks of large U.S. companies.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from large-capitalization stocks will trail returns from other asset
   classes or the overall stock market. Large-capitalization stocks tend to go
   through cycles of doing better -- or worse -- than the stock market in
   general. These periods have, in the past, lasted for as long as several
   years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. The bar chart shows the performance of the Fund's Institutional Shares
in each calendar year since the Fund's inception. (Performance information for
the Institutional Plus Shares would have been substantially similar because both
classes of shares are invested in the same portfolio securities; their returns
differ only to the extent of the differences between the expenses of the two
classes.) The table shows how the Fund's average annual returns for one and five
calendar years and since inception (for Institutional Shares) and for one
calendar year and since inception (for Institutional Plus Shares) compare with
those of the index that the Fund seeks to track. Keep in mind that the Fund's
past performance does not indicate how it will perform in the future.

                              ANNUAL TOTAL RETURNS

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was -% (quarter ended _____________ ).
<PAGE>   84
                                                                               3


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                             1 YEAR    5 YEARS  SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                          <C>       <C>      <C>
Vanguard Institutional Index Fund
    Institutional Shares                        - %       - %          - %
    Institutional Plus Shares                   -         -            -
    S&P 500 Index                               -         -            -
- --------------------------------------------------------------------------------
*July 31, 1990 for Institutional Shares; July 7, 1997 for Institutional Plus
Shares.
- --------------------------------------------------------------------------------
</TABLE>

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold shares of the Fund. The expenses shown under Annual Fund Operating Expenses
are based upon those incurred in the fiscal year ended December 31, 1998.

<TABLE>
<S>                                                                      <C>
SHAREHOLDER FEES* (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                None
Transaction Fees on Purchases:                                           None**
Sales Charge (Load) Imposed on Reinvested Dividends:                     None
Redemption Fees:                                                         None
Exchange Fees:                                                           None

INSTITUTIONAL SHARES

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
  assets)
  Management Expenses:                                                    - %
  12b-1 Marketing Fees:                                                  None
  Other Expenses:                                                         - %

     TOTAL ANNUAL FUND OPERATING EXPENSES:                                - %

INSTITUTIONAL PLUS SHARES

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
assets) 
Management Expenses:                                                      - %
12b-1 Marketing Fees:                                                    None
Other Expenses:                                                           - %

     TOTAL ANNUAL FUND OPERATING EXPENSES:                                - %
</TABLE>

*Applies to both Institutional and Institutional Plus Shares.

**The Fund reserves the right to deduct a transaction fee, ranging from 0.08% to
  0.20%, from purchases of shares.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                            1 YEAR       3 YEARS       5 YEARS     10 YEARS
- --------------------------------------------------------------------------------
<S>                         <C>          <C>           <C>         <C>
Institutional Shares         $ -          $ -          $ -           $ -
Institutional Plus Shares      -            -            -             -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.
<PAGE>   85
4

FUND PROFILE--VANGUARD INSTITUTIONAL INDEX FUND INSTITUTIONAL AND INSTITUTIONAL 
PLUS SHARES (continued)

ADDITIONAL INFORMATION -- INSTITUTIONAL SHARES

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group,
Valley Forge, Pa., since inception

INCEPTION DATE
July 31, 1990

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
  InstIdx

VANGUARD FUND NUMBER
094

CUSIP NUMBER
922040100

TICKER SYMBOL
VINIX

ADDITIONAL INFORMATION -- INSTITUTIONAL PLUS SHARES

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
July 7, 1997

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
InstPlus

VANGUARD FUND NUMBER
854

CUSIP NUMBER
922040209

TICKER SYMBOL
VIIIX
<PAGE>   86
                                                                               5


FUND PROFILE -- VANGUARD TOTAL STOCK MARKET INDEX FUND
INSTITUTIONAL SHARES

The following profile summarizes key features of Vanguard Total Stock Market
Index Fund Institutional Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of the overall stock market.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Wilshire 5000 Equity Index, which consists of all the U.S. common stocks
regularly traded on the New York and American Stock Exchanges and the Nasdaq
over-the-counter market.

PRIMARY RISK

THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
Stock markets tend to move in cycles, with periods of rising prices and periods
of falling prices.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
Institutional Shares of the Fund. The bar chart shows the Fund's performance in
the one full calendar year since inception of the Institutional class of shares.
The table shows how the Fund's average annual returns for one calendar year and
since inception compare with those of the index that the Fund seeks to track.
Keep in mind that the Fund's past performance does not indicate how it will
perform in the future.

                              ANNUAL TOTAL RETURNS

   During the period shown in the bar chart, the highest return for a calendar
quarter was  % (quarter ended _____________ ) and the lowest return for a
quarter was -  % (quarter ended _____________ ).

<TABLE>
<CAPTION>
- ------------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- ------------------------------------------------------------------------------------
                                                            1 YEAR  SINCE INCEPTION*
- ------------------------------------------------------------------------------------
<S>                                                         <C>     <C>
Vanguard Total Stock Market Index Fund Institutional Shares       %          %
Wilshire 5000 Index                                                         
- ------------------------------------------------------------------------------------
*July 7, 1997.
- ------------------------------------------------------------------------------------
</TABLE>
<PAGE>   87
6

Fund Profile--Vanguard Total Stock Market Index Fund Institutional
Shares (continued)


FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold Institutional Shares of the Fund. The expenses shown under Annual Fund
Operating Expenses are based upon those incurred in the fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                             <C>
         SHAREHOLDER FEES (fees paid directly from your investment)
         Sales Charge (Load) Imposed on Purchases:                              None
         Transaction Fees on Purchases:                                         None*
         Sales Charge (Load) Imposed on Reinvested Dividends:                   None
         Redemption Fees:                                                       None
         Exchange Fees:                                                         None

         ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
         assets)
         Management Expenses:                                                      %
         12b-1 Marketing Fees:                                                  None
         Other Expenses:                                                           %

            TOTAL ANNUAL FUND OPERATING EXPENSES:                                  %
</TABLE>

         *The Fund reserves the right to deduct a transaction fee, ranging from
          0.08% to 0.20%, from purchases of shares.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                1 YEAR            3 YEARS           5 YEARS          10 YEARS
- --------------------------------------------------------------------------------
<S>             <C>               <C>               <C>              <C>
                  $                 $                 $                 $  
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group,
Valley Forge, Pa., since inception

INCEPTION DATE
July 7, 1997

NET ASSETS AS OF DECEMBER 31, 1998
$   billion

NEWSPAPER ABBREVIATION
TotStIst

VANGUARD FUND NUMBER
855

CUSIP NUMBER
922908801

TICKER SYMBOL
VITSX
<PAGE>   88
                                                                               7


FUND PROFILE -- VANGUARD EXTENDED MARKET INDEX FUND
INSTITUTIONAL SHARES

The following profile summarizes key features of Vanguard Extended Market Index
Fund Institutional Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of mid- and small-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Wilshire 4500 Equity Index, a broadly diversified index of stocks of
medium-size and small U.S. companies. The Wilshire 4500 Index contains all of
the U.S. common stocks regularly traded on the New York and American Stock
Exchanges and the Nasdaq over-the-counter market, except those stocks included
in the S&P 500 Index.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from mid- or small-capitalization stocks will trail returns from
   other asset classes or the overall stock market. Each type of stock tends to
   go through cycles of doing better -- or worse -- than the stock market in
   general. These periods have, in the past, lasted for as long as several
   years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
Institutional Shares of the Fund. The bar chart shows the Fund's performance in
the one full calendar year since inception of the Institutional class of shares.
The table shows how the Fund's average annual returns for one calendar year and
since inception compare with those of the index that the Fund seeks to track.
Keep in mind that the Fund's past performance does not indicate how it will
perform in the future.

- -------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- -------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).

<TABLE>
<CAPTION>
- ----------------------------------------------------------------------------------------
             AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- ----------------------------------------------------------------------------------------
                                                               1 YEAR   SINCE INCEPTION*
- ----------------------------------------------------------------------------------------
<S>                                                            <C>      <C>
Vanguard Extended Market Index Fund Institutional Shares         - %           - %
Wilshire 4500 Index                                              -             -
- ----------------------------------------------------------------------------------------
*July 7, 1997.
- ----------------------------------------------------------------------------------------
</TABLE>
<PAGE>   89
8


FUND PROFILE-VANGUARD EXTENDED MARKET INDEX FUND INSTITUTIONAL SHARES
(continued)

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold Institutional Shares of the Fund. The expenses shown under Annual Fund
Operating Expenses are based upon those incurred in the fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                            <C>
         SHAREHOLDER FEES (fees paid directly from your investment)
         Sales Charge (Load) Imposed on Purchases:                              None
         Transaction Fees on Purchases:                                        0.25%*
         Sales Charge (Load) Imposed on Reinvested Dividends:                   None
         Redemption Fees:                                                       None
         Exchange Fees:                                                         None

         ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's
         assets) 
         Management Expenses:                                                    - %
         12b-1 Marketing Fees:                                                  None
         Other Expenses:                                                         - %

            TOTAL ANNUAL FUND OPERATING EXPENSES:                                - %
</TABLE>

*The transaction fee is deducted from all purchases (including exchanges from
 other Vanguard funds), but not from reinvested dividends and capital gains.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                1 YEAR            3 YEARS           5 YEARS          10 YEARS
- --------------------------------------------------------------------------------
<S>             <C>               <C>               <C>              <C>
                  $ -               $ -               $ -               $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa.,
since inception

INCEPTION DATE
July 7, 1997

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
Extndlst

VANGUARD FUND NUMBER
856

CUSIP NUMBER
922908884

TICKER SYMBOL
VIEIX
<PAGE>   90
                                                                               9


FUND PROFILE -- VANGUARD MID-CAP INDEX FUND INSTITUTIONAL SHARES

The following profile summarizes key features of Vanguard Mid-Cap Index Fund
Institutional Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of mid-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's Mid-Cap 400 Index, which is made up of a group of
medium-size U.S. companies.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from mid-capitalization stocks will trail returns from other asset
   classes or the overall stock market. Mid-capitalization stocks tend to go
   through cycles of doing better -- or worse -- than the stock market in
   general. These periods have, in the past, lasted for as long as several
   years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                   <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                              None
Transaction Fees on Purchases:                                        0.25%*
Sales Charge (Load) Imposed on Reinvested Dividends:                   None
Redemption Fees:                                                       None
Exchange Fees:                                                         None
</TABLE>

<TABLE>
<S>                                                                             <C>
ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                              -%
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                   -%

   TOTAL ANNUAL FUND OPERATING EXPENSES:                                          -%
</TABLE>

*The transaction fee is deducted from all purchases (including exchanges from
 other Vanguard funds), but not from reinvested dividends and capital gains.

   For accounts with current balances of less than $10,000, Vanguard will deduct
an account maintenance fee ($10 each December) from your annual distribution of
the Fund's dividends. If your distribution is less than the fee, fractional
shares will be automatically redeemed to make up the difference.
<PAGE>   91
10


FUND PROFILE -- VANGUARD MID-CAP INDEX FUND INSTITUTIONAL SHARES (continued)

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
                1 YEAR            3 YEARS           5 YEARS          10 YEARS
- --------------------------------------------------------------------------------
<S>                               <C>               <C>              <C>
- --------------------------------------------------------------------------------
                  $ -               $ -               $ -               $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
MidCpIst

VANGUARD FUND NUMBER
864

CUSIP NUMBER
922908835

TICKER SYMBOL
VMCIX
<PAGE>   92
                                                                              11


FUND PROFILE -- VANGUARD SMALL-CAP INDEX FUND
INSTITUTIONAL SHARES

The following profile summarizes key features of Vanguard Small-Cap Index Fund
Institutional Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Russell 2000 Index, which is made up of the stocks of smaller U.S.
companies. The Russell 2000 Index is comprised of the 2,000 smallest companies
out of the 3,000 largest U.S. companies.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from small-capitalization stocks will trail returns from other asset
   classes or the overall stock market. Small-capitalization stocks tend to go
   through cycles of doing better -- or worse -- than the stock market in
   general. These periods have, in the past, lasted for as long as several
   years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
Institutional Shares of the Fund. The bar chart shows the Fund's performance in
the one full calendar year since inception of the Institutional class of shares.
The table shows how the Fund's average annual returns for one calendar year and
since inception compare with those of the index that the Fund seeks to track.
Keep in mind that the Fund's past performance does not indicate how it will
perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------




- --------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                                      1 YEAR    SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                                   <C>       <C>
Vanguard Small-Cap Index Fund Institutional Shares       - %          - %
Russell 2000 Index                                         -            -
- --------------------------------------------------------------------------------
*July 7, 1997.
- --------------------------------------------------------------------------------
</TABLE>
<PAGE>   93
12


FUND PROFILE -- VANGUARD SMALL-CAP INDEX FUND INSTITUTIONAL SHARES (continued)

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold Institutional Shares of the Fund. The expenses shown under Annual Fund
Operating Expenses are based upon those incurred in the fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                            <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                 0.50%*
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                             - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                  - %

   TOTAL ANNUAL FUND OPERATING EXPENSES:                                         - %
</TABLE>

*The transaction fee is deducted from all purchases (including exchanges from
 other Vanguard funds), but not from reinvested dividends and capital gains.

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                1 YEAR            3 YEARS           5 YEARS          10 YEARS
- --------------------------------------------------------------------------------
<S>                               <C>               <C>              <C>
                  $ -               $ -               $ -               $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
July 7, 1997

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
SmCapIst

VANGUARD FUND NUMBER
857

CUSIP NUMBER
922908876

TICKER SYMBOL
VSCIX
<PAGE>   94
                                                                              13


FUND PROFILE -- VANGUARD VALUE INDEX FUND INSTITUTIONAL SHARES

The following profile summarizes key features of Vanguard Value Index Fund
Institutional Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization value stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's/BARRA Value Index, which includes those stocks of the
S&P 500 Index with lower than average price/book ratios.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from value stocks will trail returns from other asset classes or the
   overall stock market. Value stocks tend to go through cycles of doing better
   -- or worse -- than the stock market in general. These periods have, in the
   past, lasted for as long as several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. Because calendar year performance information for the Fund's
Institutional Shares is not yet available, the information presented in the bar
chart and table reflects the performance of the Fund's Investor Shares (which
are offered through a separate prospectus). Performance information for the
Institutional Shares would have been substantially similar because both classes
of shares are invested in the same portfolio of securities; their returns differ
only to the extent of the difference between the expenses of the two classes.

   The bar chart shows the performance of the Fund's Investor Shares in each of
the last ten calendar years. The table shows how the average annual returns for
one, five, and ten calendar years of the Fund's Investor Shares compare with
those of the index that the Fund seeks to track. Keep in mind that the Fund's
past performance does not indicate how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------




- --------------------------------------------------------------------------------

NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).
<PAGE>   95
14

FUND PROFILE - VANGUARD VALUE INDEX FUND INSTITUTIONAL SHARES (continued)
<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                         1 YEAR    5 YEARS     SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                      <C>       <C>         <C>
Vanguard Value Index Fund                  - %       - %             - %
S&P/BARRA Value Index                        -         -               -
- --------------------------------------------------------------------------------
*November 2, 1992.
- --------------------------------------------------------------------------------
</TABLE>

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold Institutional Shares of the Fund. The expenses shown under Annual Fund
Operating Expenses are based upon those incurred in the fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                          <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                    None
Transaction Fees on Purchases:                                               None
Sales Charge (Load) Imposed on Reinvested Dividends:                         None
Redemption Fees:                                                             None
Exchange Fees:                                                               None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                          - %
12b-1 Marketing Fees:                                                        None
Other Expenses:                                                               - %

   TOTAL ANNUAL FUND OPERATING EXPENSES:                                      - %
</TABLE>

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                1 YEAR            3 YEARS           5 YEARS          10 YEARS
- --------------------------------------------------------------------------------
<S>                               <C>               <C>              <C>
                  $ -               $ -               $ -               $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
July 2, 1998

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
ValueIst

VANGUARD FUND NUMBER
867

CUSIP NUMBER
922908850

TICKER SYMBOL
- -
<PAGE>   96
                                                                              15


FUND PROFILE -- VANGUARD SMALL-CAP VALUE INDEX FUND
INSTITUTIONAL SHARES

The following profile summarizes key features of Vanguard Small-Cap Value Index
Fund Institutional Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization value stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's SmallCap 600/BARRA Value Index, which includes those
stocks of the S&P SmallCap 600 Index with lower than average price/book ratios.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from small-capitalization value stocks will trail returns from other
   asset classes or the overall stock market. Small-capitalization value stocks
   tend to go through cycles of doing better -- or worse -- than the stock
   market in general. These periods have, in the past, lasted for as long as
   several years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                            <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                 1.00%*
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                             - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                  - %

   TOTAL ANNUAL FUND OPERATING EXPENSES:                                         - %
</TABLE>

*The transaction fee is deducted from all purchases (including exchanges from
 other Vanguard funds), but not from reinvested dividends and capital gains.
<PAGE>   97
16


FUND PROFILE -- VANGUARD SMALL-CAP VALUE INDEX FUND INSTITUTIONAL SHARES
(continued)

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                1 YEAR            3 YEARS           5 YEARS          10 YEARS
- --------------------------------------------------------------------------------
<S>                               <C>               <C>              <C>
                  $ -               $ -               $ -               $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
SmValIst

VANGUARD FUND NUMBER
865

CUSIP NUMBER
922908785

TICKER SYMBOL
- -
<PAGE>   98
                                                                              17


FUND PROFILE -- VANGUARD GROWTH INDEX FUND INSTITUTIONAL SHARES

The following profile summarizes key features of Vanguard Growth Index Fund
Institutional Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of large-capitalization growth stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's/BARRA Growth Index, which includes those stocks of the
S&P 500 Index with higher than average price/book ratios.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from growth stocks will trail returns from other asset classes or the
   overall stock market. Growth stocks tend to go through cycles of doing better
   -- or worse -- than the stock market in general. These periods have, in the
   past, lasted for as long as several years.

PERFORMANCE/RISK INFORMATION

The bar chart and table below provide an indication of the risk of investing in
the Fund. Because calendar year performance information for the Fund's
Institutional Shares is not yet available, the information presented in the bar
chart and table reflects the performance of the Fund's Investor Shares (which
are offered through a separate prospectus). Performance information for the
Institutional Shares would have been substantially similar because both classes
of shares are invested in the same portfolio of securities; their returns differ
only to the extent of the difference between the expenses of the two classes.

   The bar chart shows the performance of the Fund's Investor Shares in each of
the last ten calendar years. The table shows how the average annual returns for
one, five, and ten calendar years of the Fund's Investor Shares compare with
those of the index that the Fund seeks to track. Keep in mind that the Fund's
past performance does not indicate how it will perform in the future.

- --------------------------------------------------------------------------------
                              ANNUAL TOTAL RETURNS
- --------------------------------------------------------------------------------




- --------------------------------------------------------------------------------
NOTE: Return figures do not reflect the annual account maintenance fee of $10
for accounts with balances of less than $10,000.
- --------------------------------------------------------------------------------

   During the period shown in the bar chart, the highest return for a calendar
quarter was -% (quarter ended _____________ ) and the lowest return for a
quarter was - -% (quarter ended _____________ ).
<PAGE>   99
18

Fund Profile--Vanguard Growth Index Fund Institutional Shares (continued)

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
         AVERAGE ANNUAL TOTAL RETURNS FOR YEARS ENDED DECEMBER 31, 1998
- --------------------------------------------------------------------------------
                                         1 YEAR    5 YEARS    SINCE INCEPTION*
- --------------------------------------------------------------------------------
<S>                                      <C>       <C>        <C>
Vanguard Growth Index Fund                 - %       - %            - %
S&P/BARRA Growth Index                       -         -              -
- --------------------------------------------------------------------------------
*November 2, 1992.
- --------------------------------------------------------------------------------
</TABLE>

FEES AND EXPENSES

The following table describes the fees and expenses you would pay if you buy and
hold Institutional Shares of the Fund. The expenses shown under Annual Fund
Operating Expenses are based upon those incurred in the fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                             <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                  None
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                             - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                  - %

   TOTAL ANNUAL FUND OPERATING EXPENSES:                                         - %
</TABLE>

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                1 YEAR            3 YEARS           5 YEARS          10 YEARS
- --------------------------------------------------------------------------------
<S>                               <C>               <C>              <C>
                  $ -               $ -               $ -               $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Dividends are paid quarterly in March, June, September, and December; capital
gains, if any, are paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
May 14, 1998

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
GrwthIst

VANGUARD FUND NUMBER
868

CUSIP NUMBER
922908868

TICKER SYMBOL
VIGIX
<PAGE>   100
                                                                              19


FUND PROFILE--VANGUARD SMALL-CAP GROWTH INDEX FUND INSTITUTIONAL SHARES

The following profile summarizes key features of Vanguard Small-Cap Growth Index
Fund Institutional Shares.

INVESTMENT OBJECTIVE

The Fund seeks to match the performance of a benchmark index that measures the
investment return of small-capitalization growth stocks.

INVESTMENT STRATEGIES

The Fund employs a passive management strategy designed to track the performance
of the Standard & Poor's SmallCap 600/BARRA Growth Index, which includes those
stocks of the S&P SmallCap 600 Index with higher than average price/book ratios.

PRIMARY RISKS

- -  THE FUND'S TOTAL RETURN, LIKE STOCK PRICES GENERALLY, WILL FLUCTUATE WITHIN A
   WIDE RANGE, SO AN INVESTOR COULD LOSE MONEY OVER SHORT OR EVEN LONG PERIODS.
   Stock markets tend to move in cycles, with periods of rising prices and
   periods of falling prices.

- -  The Fund is also subject to investment style risk, which is the chance that
   returns from small-capitalization growth stocks will trail returns from other
   asset classes or the overall stock market. Small-capitalization growth stocks
   tend to go through cycles of doing better--or worse--than the stock
   market in general. These periods have, in the past, lasted for as long as
   several years.

PERFORMANCE/RISK INFORMATION

Calendar year performance information (which helps an investor assess a fund's
risk by showing the volatility of the fund's returns) is not yet available
because the Fund was not in operation for a full calendar year as of the date of
this prospectus.

FEES AND EXPENSES

The following table describes the fees you would pay if you buy and hold shares
of the Fund. The expenses shown under Annual Fund Operating Expenses are
estimates based upon the expenses incurred in the partial fiscal year ended
December 31, 1998.

<TABLE>
<S>                                                                            <C>
SHAREHOLDER FEES (fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases:                                       None
Transaction Fees on Purchases:                                                 1.00%*
Sales Charge (Load) Imposed on Reinvested Dividends:                            None
Redemption Fees:                                                                None
Exchange Fees:                                                                  None

ANNUAL FUND OPERATING EXPENSES (expenses deducted from the Fund's assets)
Management Expenses:                                                             - %
12b-1 Marketing Fees:                                                           None
Other Expenses:                                                                  - %

   TOTAL ANNUAL FUND OPERATING EXPENSES:                                         - %
</TABLE>

*The transaction fee is deducted from all purchases (including exchanges from
 other Vanguard funds), but not from reinvested dividends and capital gains.
<PAGE>   101
20


FUND PROFILE--VANGUARD SMALL-CAP GROWTH INDEX FUND INSTITUTIONAL SHARES
(continued)

   The following example is intended to help you compare the cost of investing
in the Fund with the cost of investing in other mutual funds. It illustrates the
hypothetical expenses that you would incur over various periods if you invest
$10,000 in the Fund. This example assumes that the Fund provides a return of 5%
a year, and that operating expenses remain the same. The results apply whether
or not you redeem your investment at the end of each period.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                1 YEAR            3 YEARS           5 YEARS          10 YEARS
- --------------------------------------------------------------------------------
<S>                               <C>               <C>              <C>
                  $ -               $ -               $ -               $ -
- --------------------------------------------------------------------------------
</TABLE>

   THIS EXAMPLE SHOULD NOT BE CONSIDERED TO REPRESENT ACTUAL EXPENSES OR
PERFORMANCE FROM THE PAST OR FOR THE FUTURE. ACTUAL FUTURE EXPENSES MAY BE
HIGHER OR LOWER THAN THOSE SHOWN.

ADDITIONAL INFORMATION

DIVIDENDS AND CAPITAL GAINS
Paid annually in December

INVESTMENT ADVISER
Vanguard Core Management Group, Valley Forge, Pa., since inception

INCEPTION DATE
May 21, 1998

NET ASSETS AS OF DECEMBER 31, 1998
$ - billion

NEWSPAPER ABBREVIATION
SmGthIst

VANGUARD FUND NUMBER
866

CUSIP NUMBER
922908819

TICKER SYMBOL
- -
<PAGE>   102
                                                                              21


MORE ON THE FUNDS

The following sections discuss other important features of Vanguard
Institutional Index Fund and the Vanguard U.S. Stock Index Funds.

INDEXING METHODS

In seeking to track a particular index, a fund generally uses one of two methods
to select stocks.

   Some index funds hold each stock found in their target indexes in about the
same proportions as represented in the indexes themselves. This is called a
"replication" method. For example, if 5% of the S&P 500 Index were made up of
the stock of a specific company, a fund tracking that index (such as the
Institutional Index Fund) would invest about 5% of its assets in that company.
The Institutional Index Fund and the Mid-Cap, Value, Small-Cap Value, Growth,
and Small-Cap Growth Index Funds employ this method of indexing.

   Because it would be very expensive to buy and sell all of the stocks held in
certain indexes (the Wilshire 5000 Index, for example, includes more than 7,200
stocks), funds tracking these larger indexes use a "sampling" technique. Using a
sophisticated computer program, these funds select a representative sample of
stocks from their target index that will resemble the full index in terms of
industry weightings, market capitalization, price/earnings ratio, dividend
yield, and other characteristics. For instance, if 10% of the Wilshire 5000
Index were made up of utility stocks, the Total Stock Market Index Fund would
invest about 10% of its assets in some--but not all--of those utility
stocks. The particular utility stocks selected by the Fund, as a group, would
have investment characteristics similar to those of the utility stocks in the
Index. The Total Stock Market, Extended Market, and Small-Cap Index Funds employ
this method of indexing.

   The following table shows the number of stocks held by each of the Funds as
of December 31, 1998.

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------
         FUND                   NUMBER OF STOCKS HELD    NUMBER OF STOCKS IN TARGET INDEX
- -----------------------------------------------------------------------------------------
<S>                             <C>                      <C>
Institutional Index
Total Stock Market
Extended Market
Mid-Cap
Small-Cap
Value
Small-Cap Value
Growth
Small-Cap Growth
- -----------------------------------------------------------------------------------------
</TABLE>

                                PLAIN TALK ABOUT

                          GROWTH FUNDS AND VALUE FUNDS

Growth investing and value investing are two styles employed by stock fund 
managers. Growth funds generally focus on companies believed to have 
above-average potential for growth in revenue and earnings. Reflecting the 
market's high expectations for superior growth, the prices of such stocks are 
typically above-average in relation to such measures as revenue, earnings, book 
value, and dividends. Value funds generally emphasize companies from which the 
market does not expect strong growth. The prices of value stocks typically are 
below-average in comparison to such factors as earnings and book value, and 
these stocks typically pay above-average dividend yields. Growth and value 
stocks have, in the past, produced similar long-term returns, though each 
category has periods when it outperforms the other. In general, growth funds 
appeal to investors who will accept more volatility in hopes of a greater 
increase in share price. Growth funds also may appeal to investors with taxable 
accounts who want a higher proportion of returns to come as capital gains 
(which may be taxed at lower rates than dividend income). Value funds, by 
contrast, are appropriate for investors who want some dividend income and the 
potential for capital gains, but are less tolerant of share-price fluctuations.
<PAGE>   103
22


ADDITIONAL RISK INFORMATION

[FLAG] EACH FUND IS SUBJECT TO MARKET RISK, WHICH IS THE POSSIBILITY THAT STOCK
PRICES OVERALL WILL DECLINE OVER SHORT OR EVEN LONG PERIODS. STOCK MARKETS TEND
TO MOVE IN CYCLES, WITH PERIODS OF RISING STOCK PRICES AND PERIODS OF FALLING
STOCK PRICES.

   To illustrate the volatility of stock prices, the following table shows the
best, worst, and average total returns for the U.S. stock market over various
periods as measured by the S&P 500 Index, which--in addition to being the
target index for the Institutional Index Fund--is a widely used barometer of
stock market activity. (Total returns consist of dividend income plus change in
market price.) Note that the returns shown do not include the costs of buying
and selling stocks or other expenses that a real-world investment portfolio
would incur. Note, also, that the gap between best and worst tends to narrow
over the long term.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                     U.S. STOCK MARKET RETURNS (1926-1998)
- --------------------------------------------------------------------------------
                                  1 YEAR      5 YEARS     10 YEARS     20 YEARS
- --------------------------------------------------------------------------------
<S>                               <C>         <C>         <C>          <C>
Best                               54.2%       24.1%        19.9%        17.7%
Worst                             -43.1       -12.4         -0.8          3.1
Average                            13.1        10.7         11.0         11.0
- --------------------------------------------------------------------------------
</TABLE>

   The table covers all of the 1-, 5-, 10-, and 20-year periods from 1926
through 1998. You can see, for example, that while the average return on stocks
for all of the 5-year periods was 10.7%, returns for individual 5-year periods
ranged from a -12.4% average (from 1928 through 1932) to 24.1% (from 1994
through 1998). These average returns reflect past performance on common stocks;
you should not regard them as an indication of future returns from either the
stock market as a whole or any of the Funds in particular.

   Keep in mind that the S&P 500 Index tracks mainly large-capitalization
stocks. Historically, the mid- and small-cap stocks of the Wilshire 4500, S&P
MidCap 400, and Russell 2000 Indexes (the target indexes for the Extended
Market, Mid-Cap, and Small-Cap Index Funds, respectively) have been more
volatile than--and at times have performed quite differently from--the
large-cap stocks of the S&P 500 Index.

   Even indexes that are subsets of the S&P 500 Index--such as the S&P/BARRA
Value Index and the S&P/BARRA Growth Index (the target indexes for the Value and
Growth Index Funds)--will not perform in the same way as the broader S&P 500
Index. Historically, stocks of the S&P/BARRA Value Index have been less volatile
than the stocks found in the broader S&P 500 Index; stocks of the S&P/BARRA
Growth Index, on the other hand, have displayed somewhat greater short-term
volatility than the S&P 500 Index's stocks. Historical performance aside,
however, both value and growth stocks have the potential at times to be more
volatile than the broader market.

[FLAG] THE FUNDS ARE ALSO SUBJECT, IN VARYING DEGREES, TO INVESTMENT STYLE RISK,
WHICH IS THE POSSIBILITY THAT RETURNS FROM A SPECIFIC TYPE OF STOCK (FOR
INSTANCE, SMALL-CAP OR VALUE) WILL TRAIL RETURNS FROM OTHER ASSET CLASSES OR THE
OVERALL STOCK MARKET. EACH TYPE OF STOCK TENDS TO GO THROUGH CYCLES OF DOING
BETTER--OR WORSE--THAN COMMON STOCKS IN GENERAL. THESE PERIODS HAVE, IN THE
PAST, LASTED FOR AS LONG AS SEVERAL YEARS.

TRANSACTION FEES AND ACCOUNT MAINTENANCE

Some of Vanguard's index funds charge a transaction fee on purchases of fund
shares to offset the higher costs of trading certain securities, particularly
small-company stocks. The transaction fee ensures that these higher costs are

                                PLAIN TALK ABOUT

                            LARGE-CAP, MID-CAP, AND
                                SMALL-CAP STOCKS

Stocks of publicly traded companies--and mutual funds that hold these 
stock--can be classified by the companies' market value, or capitalization. 
Generally, Vanguard defines large-capitalization (large-cap) funds as those 
holding stocks of companies whose outstanding shares have a market value 
exceeding $10 billion. Mid-cap funds hold stocks of companies with a 
market value between $1 billion and $10 billion. Small-cap funds typically hold 
stocks of companies with a market value of less than $1 billion.
<PAGE>   104
                                                                              23


borne by the investors making the transactions--and not by shareholders
already in the fund. Without transaction fees, an index fund would have trouble
tracking its target index.

   In addition, most of Vanguard's index funds charge an account maintenance fee
on accounts under $10,000 to divide the costs of maintaining accounts equitably
among shareholders.

   At Vanguard, fees are paid directly into the fund itself (unlike the sales
charge or load imposed by many fund companies, which ends up in the pocket of
the sponsor, adviser, or sales representative).

COSTS AND MARKET-TIMING

Some investors try to profit from a strategy called market-timing--switching
money into investments when they expect prices to rise, and taking money out
when they expect prices to fall. As money is shifted in and out, a fund incurs
expenses for buying and selling securities. These costs are borne by all fund
shareholders, including the long-term investors who do not generate the costs.
Therefore, the Institutional Index Fund and the Vanguard U.S. Stock Index Funds
have adopted the following policies, among others, designed to discourage
short-term trading:

- -  Each Fund reserves the right to reject any purchase request--including
   exchanges from other Vanguard funds--that it regards as disruptive to the
   efficient management of the Fund. This could be because of the timing of the
   investment or because of a history of excessive trading by the investor.

- -  Five of the Funds (Extended Market, Mid-Cap, Small-Cap, Small-Cap Value, and
   Small-Cap Growth) charge a transaction fee on purchases.

- -  There is a limit on the number of times you can exchange into and out of a
   Fund (see "Redeeming Shares" in the INVESTING WITH VANGUARD section).

- -  Telephone and online exchanges are not permitted for non-IRA accounts.

   THE VANGUARD FUNDS DO NOT PERMIT MARKET-TIMING. DO NOT INVEST IN THESE FUNDS
IF YOU ARE A MARKET-TIMER.

TURNOVER RATE

Although each Fund seeks to invest for the long term, the Funds retain the right
to sell securities regardless of how long the securities have been held.
Generally, a passively managed fund sells securities only to respond to
redemption requests or to adjust the number of shares held to reflect a change
in the fund's target index. Because of this, the turnover rate for the Funds has
been extremely low, with averages over the past five years (or since inception)
ranging from 2% for the Total Stock Market Index Fund to 29% for the Small-Cap
Index Fund. (A turnover rate of 100% would occur, for example, if a Fund sold
and replaced securities valued at 100% of its total net assets within a one-year
period.) The turnover rate of each Fund for each of the last five years (or
since inception of the applicable share class, if shorter) is shown in the
FINANCIAL HIGHLIGHTS section of this prospectus.

INVESTMENT POLICIES

Each Fund reserves the right to substitute a different index for the index it
currently tracks if the current index is discontinued or for any other reason
determined in good faith by the Fund's Board of Trustees. In every such
instance, the substitute index will measure the same general market (large-,
mid-, or small-cap, growth, or value) as the current index.

   Each Fund may invest in foreign securities to the extent necessary to carry
out its investment strategy of holding all, or a representative sample, of the
stocks that comprise the index it tracks. It is not expected that any Fund will
invest more than 5% of its assets in foreign securities.

                                PLAIN TALK ABOUT

                                  TURNOVER RATE

Before investing in a mutual fund, you should review its turnover rate. This
gives an indication of how transaction costs could affect the fund's future
returns. In general, the greater the volume of buying and selling by the fund,
the greater the impact that brokerage commissions and other transaction costs
will have on its return. Also, funds with high turnover rates may be more likely
to generate capital gains that must be distributed to shareholders as income
subject to taxes. The average turnover rate for passively managed domestic
equity index funds investing in common stocks is roughly -%; for all domestic
stock funds, the average turnover rate is approximately -%, according to
Morningstar, Inc.
<PAGE>   105
24

   Although index funds, by their nature, tend to be tax-efficient investment
vehicles, the Funds generally are managed without regard to tax ramifications.

   To track their target indexes as closely as possible, the Funds attempt to
remain fully invested in stocks. To help stay fully invested, and to reduce
transaction costs, the Funds may invest, to a limited extent, in stock futures
and options contracts, warrants, convertible securities, and swap agreements,
which are types of derivatives.

   Losses (or gains) involving futures can sometimes be substantial--in part
because a relatively small price movement in a futures contract may result in an
immediate and substantial loss (or gain) for a fund. Similar risks exist for
warrants (securities that permit their owners to purchase a specific number of
stock shares at a predetermined price), convertible securities (securities that
may be exchanged for another asset), and swap agreements (contracts which each
party agrees to make payments to the other based on the return of a specified
index or asset).

   For this reason, the Funds will not use futures, options, warrants,
convertible securities, or swap agreements for speculative purposes or as
leveraged investments that magnify the gains or losses of an investment. The
value of all futures contracts in which any Fund acquires an interest cannot
exceed 20% of that Fund's total assets.

   The reasons for which a Fund will invest in futures and options are:

- -  To keep cash on hand to meet shareholder redemptions or other needs while
   simulating full investment in stocks.

- -  To reduce the Fund's transaction costs or add value when these instruments
   are favorably priced.

THE FUNDS AND VANGUARD

Vanguard U.S. Stock Index Funds are members of The Vanguard Group, a family of
more than 35 investment companies with more than 100 distinct investment
portfolios holding assets worth more than $- billion.* All of the funds that are
members of The Vanguard Group share in the expenses associated with business
operations, such as personnel, office space, equipment, and advertising.

   Vanguard also provides marketing services to the member funds. Although
shareholders do not pay sales commissions or 12b-1 distribution fees, each fund
pays its allocated share of The Vanguard Group's marketing costs.

*Vanguard Institutional Index Fund is not a member of The Vanguard Group, but is
 administered by Vanguard and pays Vanguard a fee to provide management,
 advisory, marketing, and other services.

INVESTMENT ADVISER

Vanguard Core Management Group (the "Group"), P.O. Box 2600, Valley Forge, PA
19482, provides advisory services to the Funds.

   Under the terms of a service and advisory agreement, Vanguard pays for all of
the Institutional Index Fund's expenses (except taxes and brokerage
commissions). In exchange, the Fund pays Vanguard a monthly management fee based
on an annual rate of 0.06% of the average daily net assets of the Institutional
Shares and 0.025% of the average daily net assets of the Institutional Plus
Shares.

   Each of the Vanguard U.S. Stock Index Funds receives advisory services from
Vanguard on an at-cost basis. For the fiscal year ended December 31, 1998, the
Institutional Share classes of those Funds paid fees for these services at an
effective annual rate (applied to the average daily net assets of each Fund) of
- -% for the Total Stock Market Index Fund; -% for the Extended Market Index Fund;
and -% for the Small-Cap Index Fund. As of the date of this prospectus, the
Institutional Share classes of the Mid-Cap, Value, Small-Cap Value, Growth, and
Small-Cap Growth Index Funds had not existed for a full fiscal year; if they
had, it is estimated that they would have paid advisory fees (applied to average
daily net assets) of -%, -%, -%, -%, and -%, respectively.

                                PLAIN TALK ABOUT

                      VANGUARD'S UNIQUE CORPORATE STRUCTURE

The Vanguard Group is truly a MUTUAL mutual fund company. It is owned jointly by
the funds it oversees and thus indirectly by the shareholders in those funds.
Most other mutual funds are operated by for-profit management companies that may
be owned by one person, by a group of individuals, or by investors who own the
management company's stock. By contrast, Vanguard provides its services on an
"at-cost" basis, and the funds' expense ratios reflect only these costs. No
separate management company reaps profits or absorbs losses from operating the
funds.
<PAGE>   106
                                                                              25

                                PLAIN TALK ABOUT

                               THE FUNDS' ADVISER

Vanguard Core Management Group provides investment advisory services to many
Vanguard funds. As of December 31, 1998, the Group managed more than $- billion
in total assets. The individual responsible for overseeing each Fund's
investments is:

   GEORGE U. SAUTER, Managing Director of Vanguard; has worked in investment
management since 1985; with Vanguard since 1987; A.B., Dartmouth College;
M.B.A., University of Chicago.

   The Funds have authorized the Group to choose brokers or dealers to handle
the purchase and sale of securities for the Funds, and to get the best available
price and most favorable execution from these brokers with respect to all
transactions. Also, the Funds may direct the Group to use a particular broker
for certain transactions in exchange for commission rebates or research services
provided to the Funds.

YEAR 2000 CHALLENGE

The common practice in computer programming of using just two digits to identify
a year has resulted in the Year 2000 challenge throughout the information
technology industry. If unchanged, many computer applications and systems could
misinterpret dates occurring after December 31, 1999, leading to errors or
failure. Such failure could adversely affect a fund's operations, including
pricing, securities trading, and the servicing of shareholder accounts.

   The Vanguard Group is dedicated to providing uninterrupted, high-quality
performance from our computer systems before, during, and after 2000. In July
1998, we completed the renovation and initial testing of our internal systems.
Vanguard is diligently working with external partners, suppliers, and vendors,
including fund managers and other service providers, to assure that the systems
with which we interact remain operational at all times.

   In addition to taking every reasonable step to secure our internal systems
and external relationships, Vanguard is further developing contingency plans
intended to assure that unexpected systems failures will not adversely affect
the Funds' operations. Vanguard intends to monitor these processes through the
rollover of 1999 into 2000 and to quickly implement alternate solutions if
necessary.

   However, despite Vanguard's efforts and contingency plans, noncompliant
computer systems could have a material adverse effect on a Fund's business,
operations, or financial condition. Additionally, a Fund's performance could be
hurt if a computer-system failure at a company or governmental unit affects the
price of securities the Fund owns.

DIVIDENDS, CAPITAL GAINS, AND TAXES

The Funds distribute to shareholders virtually all of their net income (interest
and dividends less expenses) as well as any capital gains realized from the sale
of their holdings. Income distributions for the Total Stock Market, 500, Value,
and Growth Index Funds generally occur in March, June, September, and December;
income distributions for the Extended Market, Mid-Cap, Small-Cap, Small-Cap
Value, and Small-Cap Growth Index Funds generally occur in December. Capital
gains distributions for all nine Funds generally occur in December. In addition,
the Funds may occasionally be required to make supplemental dividend or capital
gains distributions at some other time during the year.

   You can receive distributions of income or capital gains in cash, or you can
have them automatically invested in more shares of a Fund. In either case, these
distributions are taxable to you. It is important to note that distributions of
dividends and capital gains that are declared in December -- if paid to you by
the end of January -- are taxed as if they had been paid to you in December.

   Vanguard will send you a statement each year showing the tax status of all
your distributions. If you have chosen to receive dividend and/or capital gains
distributions in cash, and the postal or other delivery service is unable to
deliver checks to your address of record, we will change the distribution option
so that all dividends and other distributions are automatically invested in
additional shares. We will not pay interest on uncashed distribution checks.
<PAGE>   107
26

                                PLAIN TALK ABOUT

                                  DISTRIBUTIONS

As a shareholder, you are entitled to your share of the fund's income from
interest and dividends, and gains from the sale of investments. You receive such
earnings as either an income dividend or a capital gains distribution. Income
dividends come from both the dividends that the fund earns from its holdings and
the interest it receives from its money market and bond investments. Capital
gains are realized whenever the fund sells securities for higher prices than it
paid for them. The capital gains are either short-term or long-term depending on
whether the fund held the securities for less than or more than one year.

- -  The dividends and short-term capital gains that you receive are considered
   ordinary income for tax purposes.

- -  Any distributions of net long-term capital gains by a Fund are taxable to you
   as long-term capital gains, no matter how long you've owned shares in the
   Fund.

- -  Although the Funds do not seek to realize any particular amount of capital
   gains during a year, such gains are realized from time to time as by-products
   of their ordinary investment activities. Consequently, distributions may vary
   considerably from year to year.

- -  If you sell or exchange shares, any gain or loss you have is a taxable event.
   This means that you may have a capital gain to report as income, or a capital
   loss to report as a deduction, when you complete your federal income tax
   return.

- -  Distributions of dividends or capital gains, and capital gains or losses from
   your sale or exchange of Fund shares, may be subject to state and local
   income taxes as well.

   The tax information in this prospectus is provided as general information and
will not apply to you if you are investing through a tax-deferred account such
as an IRA or a qualified employee benefit plan. (Non-U.S. investors may be
subject to U.S. withholding and estate tax.) You should consult your tax adviser
about the tax consequences of an investment in one or more of the Funds.

   IMPORTANT NOTE: By law, each Fund must withhold 31% of your taxable
distributions and any redemption proceeds if you do not provide your correct
taxpayer identification number, or certify that it is correct, or if the IRS
instructs the Fund to do so.

SHARE PRICE

Each Fund's share price, called its net asset value, or NAV, is calculated each
business day after the close of trading on the New York Stock Exchange (the NAV
is not calculated on holidays or other days the Exchange is closed). Net asset
value per share is computed by adding up the total value of the Fund's
investments and other assets, subtracting any of its liabilities (debts), and
then dividing by the number of Fund shares outstanding:

                                         TOTAL ASSETS   -   LIABILITIES
                                         ------------------------------
                NET ASSET VALUE    =      NUMBER OF SHARES OUTSTANDING

   Knowing the daily net asset value is useful to you as a shareholder because
it indicates the current value of your investment. The Fund's NAV, multiplied by
the number of shares you own, gives you the dollar amount you would have
received had you sold all of your shares back to the Fund that day.

   A NOTE ON PRICING: A Fund's investments will be priced at their market value
when market quotations are readily available. When these quotations are not
readily available, investments will be priced at their fair value, calculated
according to procedures adopted by the Funds' Board of Trustees.

   Each Fund's share price can be found daily in the mutual fund listings of
most major newspapers under the heading "Vanguard Index Funds." Different
newspapers use different abbreviations for each Fund, but the most common are
INSTLDX, INSTPLUS, TOTSTLST, EXTNDLST, MIDCPLST, SMCAPLST, VALUELST, SMVALLST,
GRWTHLST, AND SMGTHLST.
<PAGE>   108
                                                                              27

FINANCIAL HIGHLIGHTS

The following financial highlights tables are intended to help you understand
each Fund's financial performance for the past five years or since inception*,
and certain information reflects financial results for a single Fund share in
each case. The total returns in each table represent the rate that an investor
would have earned or lost each period on an investment in the Fund (assuming
reinvestment of all dividends and distributions). This information has been
derived from the financial statements audited by PricewaterhouseCoopers LLP,
independent accountants, whose report -- along with the Funds' financial
statements -- is included in the Institutional Index Fund's and the U.S. Stock
Index Funds' most recent annual reports to shareholders. You may have the annual
reports for the Institutional Index Fund and the U.S. Stock Index Funds sent to
you without charge by contacting Vanguard.

*Because the Mid-Cap, Small-Cap Value, and Small-Cap Growth Index Funds did not
 begin operations -- and thus offering Institutional Shares -- until May 21,
 1998, tables are not included for these Funds; in addition, because the Growth
 and Value Index Funds did not begin offering Institutional Shares until May 14,
 1998, and July 2, 1998, respectively, tables are not included for these Funds.

<TABLE>
<CAPTION>
                                                                                VANGUARD INSTITUTIONAL INDEX FUND
                                                                                      INSTITUTIONAL SHARES
                                                                                     YEAR ENDED DECEMBER 31,
                                                            1998               1997             1996            1995           1994
<S>                                                         <C>         <C>              <C>             <C>            <C>
- ------------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF YEAR                             -        $     68.86      $     57.93     $     43.22    $     44.20
- ------------------------------------------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
  Net Investment Income                                        -              1.391             1.38            1.28           1.23
  Net Realized and Unrealized Gain (Loss)
     on Investments                                            -             21.415            11.90           14.86           (.66)
                                                            ------------------------------------------------------------------------
   Total from Investment Operations                            -             22.806           13.28           16.14            .57
                                                            ------------------------------------------------------------------------
DISTRIBUTIONS

  Dividends from Net Investment Income                         -             (1.391)           (1.36)          (1.27)         (1.21)
  Distributions from Realized Capital Gains                    -              (.715)            (.99)           (.16)          (.34)
                                                            ------------------------------------------------------------------------
   Total Distributions                                         -             (2.106)           (2.35)          (1.43)         (1.55)
- ------------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR                                   -        $     89.56      $     68.86     $     57.93    $     43.22
====================================================================================================================================
TOTAL RETURN                                                   -              33.36%           23.06%          37.60%          1.31%
====================================================================================================================================
RATIOS/SUPPLEMENTAL DATA

  Net Assets, End of Year (Millions)                            -       $    15,348      $    11,426     $     6,674    $     3,265
  Ratio of Total Expenses to Average Net Assets                 -              0.06%            0.06%           0.06%          0.07%
  Ratio of Net Investment Income to Average Net Assets          -              1.77%            2.18%           2.49%          2.80%
  Turnover Rate*                                                -                 7%               9%              4%            23%
- ------------------------------------------------------------------------------------------------------------------------------------
</TABLE>
*Turnover rates excluding in-kind redemptions were 6%, 9%, 4%, 19%, and 3%,
 respectively.

   From time to time, the Vanguard funds advertise yield and total return
figures. Yield is a measure of past dividend income. Total return includes both
past dividend income (assuming that it has been reinvested) plus realized and
unrealized capital appreciation (or depreciation). Neither yield nor total
return should be used to predict the future performance of a fund. 

                                PLAIN TALK ABOUT

                   HOW TO READ THE FINANCIAL HIGHLIGHTS TABLE

This explanation uses the Total Stock Market Index Fund Institutional Shares as
an example. The Fund began fiscal 1998 with a net asset value (price) of $- per
share. During the period, the Fund earned $- per share from investment income
(interest and dividends) and $- per share from investments that had appreciated
in value or that were sold for higher prices than the Fund paid for them.

   Shareholders received $- per share in the form of dividend and capital gains
distributions. A portion of each year's distributions may come from the prior
year's income or capital gains.

   The earnings ($- per share) minus the distributions ($- per share) resulted
in a share price of $- at the end of the period. This was an increase of $-
per share (from $- at the beginning of the period to $- at the end of the
period). For a shareholder who reinvested the distributions in the purchase of
more shares, the total return from the Fund was -% for the period.

   As of December 31, 1998, the Fund had $- billion in net assets. For the
year, its expense ratio was -% ($- per $1,000 of net assets); and its net
investment income amounted to -% of its average net assets. It sold and
replaced securities valued at -% of its net assets.
<PAGE>   109
28

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------------------------
                                                           VANGUARD INSTITUTIONAL INDEX FUND
                                                               INSTITUTIONAL PLUS SHARES
                                                          YEAR ENDED                    JUL. 7* TO
                                                   DECEMBER 31, 1998                 DEC. 31, 1997
- --------------------------------------------------------------------------------------------------
<S>                                                <C>                               <C>
NET ASSET VALUE, BEGINNING OF PERIOD                               -                 $       84.91
- --------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
   Net Investment Income                                           -                          .681
   Net Realized and Unrealized Gain (Loss) on Investments          -                         5.455
                                                                 ---------------------------------
      Total from Investment Operations                             -                         6.136
                                                                 ---------------------------------
DISTRIBUTIONS
   Dividends from Net Investment Income                            -                         (.866)
   Distributions from Realized Capital Gains                       -                         (.620)
                                                                 ---------------------------------
      Total Distributions                                          -                        (1.486)
- --------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD                                     -                 $       89.56
==================================================================================================

TOTAL RETURN                                                       -                          7.29%
==================================================================================================

RATIOS/SUPPLEMENTAL DATA
  Net Assets, End of Period (Millions)                             -                 $       3,488
  Ratio of Total Expenses to Average Net Assets                    -                         0.025%**
  Ratio of Net Investment Income to Average Net Assets             -                          1.72%**
  Turnover Rate                                                    -                             7%+
- --------------------------------------------------------------------------------------------------
</TABLE>

 *Commencement of operations.
**Annualized.
 +Turnover rate excluding in-kind redemptions was 6%.


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------------------------
                                                         VANGUARD TOTAL STOCK MARKET INDEX FUND
                                                                   INSTITUTIONAL SHARES
                                                          YEAR ENDED                    JUL. 7* TO
                                                   DECEMBER 31, 1998                 DEC. 31, 1997
- --------------------------------------------------------------------------------------------------
<S>                                                <C>                               <C>
NET ASSET VALUE, BEGINNING OF PERIOD                               -                 $      21.27
- --------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
   Net Investment Income                                           -                         .172
   Net Realized and Unrealized Gain (Loss) on Investments          -                        1.642
                                                                 ---------------------------------
      Total from Investment Operations                             -                        1.814
                                                                 ---------------------------------
DISTRIBUTIONS
   Dividends from Net Investment Income                            -                        (.214)
   Distributions from Realized Capital Gains                       -                        (.230)
                                                                 ---------------------------------
      Total Distributions                                          -                        (.444)
- --------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD                                     -                 $      22.64
=================================================================================================

TOTAL RETURN                                                       -                         8.60%
=================================================================================================

RATIOS/SUPPLEMENTAL DATA
  Net Assets, End of Period (Millions)                             -                 $      1,504
  Ratio of Total Expenses to Average Net Assets                    -                         0.10%**
  Ratio of Net Investment Income to Average Net Assets             -                         1.70%**

  Turnover Rate                                                    -                            2%
- --------------------------------------------------------------------------------------------------
</TABLE>
 *Inception.
**Annualized.
<PAGE>   110
                                                                              29


<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------------------------
                                                           VANGUARD EXTENDED MARKET INDEX FUND
                                                                   INSTITUTIONAL SHARES
                                                          YEAR ENDED                    JUL. 7* TO
                                                   DECEMBER 31, 1998                 DEC. 31, 1997
- --------------------------------------------------------------------------------------------------
<S>                                                <C>                               <C>
NET ASSET VALUE, BEGINNING OF PERIOD                               -                 $     29.28
- --------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
   Net Investment Income                                           -                        .200
   Net Realized and Unrealized Gain (Loss) on Investments          -                       3.191
                                                                ----------------------------------
      Total from Investment Operations                             -                       3.391
                                                                ----------------------------------

DISTRIBUTIONS
   Dividends from Net Investment Income                            -                       (.371)
   Distributions from Realized Capital Gains                       -                      (1.540)
                                                                ----------------------------------
      Total Distributions                                          -                      (1.911)
- --------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD                                     -                 $     30.76
==================================================================================================

TOTAL RETURN**                                                     -                       11.82%
==================================================================================================

RATIOS/SUPPLEMENTAL DATA
  Net Assets, End of Period (Millions)                             -                 $       415
  Ratio of Total Expenses to Average Net Assets                    -                        0.10%+
  Ratio of Net Investment Income to Average Net Assets             -                        1.43%+
  Turnover Rate                                                    -                          15%++
- --------------------------------------------------------------------------------------------------
</TABLE>
 *Inception.
**Total return does not reflect transaction fees on purchases (0.25% from
  November 3, 1997, through December 31, 1997; 0.5% from inception through
  October 31, 1997).
 +Annualized.
++Turnover rate excluding in-kind redemptions was 14%.

<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------------------------
                                                               VANGUARD SMALL-CAP INDEX FUND
                                                                   INSTITUTIONAL SHARES
                                                          YEAR ENDED                    JUL. 7* TO
                                                   DECEMBER 31, 1998                 DEC. 31, 1997
- --------------------------------------------------------------------------------------------------
<S>                                                <C>                               <C>
NET ASSET VALUE, BEGINNING OF PERIOD                               -                 $     22.56
- --------------------------------------------------------------------------------------------------
INVESTMENT OPERATIONS
   Net Investment Income                                           -                        .158
   Net Realized and Unrealized Gain (Loss) on Investments          -                       2.370
                                                                ----------------------------------
      Total from Investment Operations                             -                       2.528
                                                                ----------------------------------

DISTRIBUTIONS
   Dividends from Net Investment Income                            -                       (.288)
   Distributions from Realized Capital Gains                       -                      (1.050)
                                                                ----------------------------------
      Total Distributions                                          -                      (1.338)
- --------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD                                     -                 $     23.75
==================================================================================================

TOTAL RETURN**                                                     -                       11.42%
==================================================================================================

RATIOS/SUPPLEMENTAL DATA
  Net Assets, End of Period (Millions)                             -                 $       137
  Ratio of Total Expenses to Average Net Assets                    -                        0.12%+
  Ratio of Net Investment Income to Average Net Assets             -                        1.52%+

  Turnover Rate                                                    -                          29%
- --------------------------------------------------------------------------------------------------
</TABLE>
 *Inception.
**Total return does not reflect the 0.5% transaction fee on purchases.
 +Annualized.

"Standard & Poor's(R)," "S&P(R)," "S&P 500(R)," "Standard & Poor's 500," "500,"
"S&P MidCap 400," and "S&P SmallCap 600" are trademarks of The McGraw-Hill
Companies, Inc., and have been licensed for use by Vanguard U.S.Stock Index
Funds, Vanguard Institutional Index Fund, and The Vanguard Group. These mutual
funds are not sponsored, endorsed, sold, or promoted by Standard & Poor's, and
Standard & Poor's makes no representation regarding the advisability of
investing in the Funds. "Wilshire 4500" and "Wilshire 5000" are registered
trademarks of Wilshire Associates. Frank Russell Company is the owner of the
trademarks and copyrights relating to the Russell Indexes.
<PAGE>   111
30

INVESTING WITH VANGUARD

Are you looking for the most convenient way to open or add money to a Vanguard
account? Obtain instant access to fund information?

   Vanguard can help. Our goal is to make it easy and pleasant for you to do
business with us.

   The following sections of the prospectus briefly explain the many services we
offer. Booklets providing detailed information are available on the services
marked with a [BOOK]. Please call us to request copies.

SERVICES AND ACCOUNT FEATURES

Vanguard offers many services that make it convenient to buy, sell, or exchange
shares, or to obtain fund or account information.

TELEPHONE REDEMPTIONS (SALES AND EXCHANGES)

Automatically set up for these Funds unless you notify us otherwise.

VANGUARD AUTOMATIC EXCHANGE SERVICE(TM) [BOOK]

Automatic method for moving a fixed amount of money from one Vanguard fund
account to another.

VANGUARD TELE-ACCOUNT(R) 1-800-662-6273 (ON-BOARD) [BOOK]

Toll-free 24-hour access to Vanguard fund and account information -- as well as
some transactions -- by using any touch-tone phone. Tele-Account provides total
return, share price, price change, and yield quotations for all Vanguard funds;
gives your account balances and history (e.g., last transaction, latest dividend
distribution); and allows you to sell or exchange fund shares.

ACCESS VANGUARD(TM) www.vanguard.com [COMPUTER]

You can use your personal computer to perform certain transactions for most
Vanguard funds by accessing our website. To establish this service, you must
register through the website. We will then send to you, by mail, an account
access password that allows you to process the following financial and
administrative transactions online:

- -  Open a new account.*

- -  Buy, sell, or exchange shares of most funds.

- -  Change your name/address.

- -  Add/change fund options (including dividend options, bank instructions,
   checkwriting, and Vanguard Automatic Exchange Service).

*Only current Vanguard shareholders can open a new account online, by exchanging
 shares from other existing Vanguard accounts.

SERVICES FOR CLIENTS OF VANGUARD'S INSTITUTIONAL DIVISION: 1-888-809-8102

Vanguard's Institutional Division offers a variety of specialized services for
large institutional investors, including the ability to effect account
transactions through private electronic networks.

TYPES OF ACCOUNTS

Individuals and institutions can establish a variety of accounts with Vanguard.

FOR ONE OR MORE PEOPLE

Open an account in the name of one (individual) or more (joint tenants) people.

FOR HOLDING PERSONAL TRUST ASSETS [BOOK]

Invest assets held in an existing personal trust.

FOR AN ORGANIZATION

Open an account as a corporation, partnership, endowment, foundation, or other
entity.
<PAGE>   112
                                                                              31


A NOTE ON INVESTING WITH VANGUARD THROUGH OTHER FIRMS

You may purchase or sell Fund shares through a financial intermediary such as a
bank, broker, or investment adviser. If you invest with Vanguard through an
intermediary, please read that firm's program materials carefully to learn of
any special rules that may apply. For example, special terms may apply to
additional service features, fees, or other policies. Consult your intermediary
to determine when your order will be priced.

BUYING SHARES

You buy your shares at the Fund's next-determined net asset value after Vanguard
receives your request. As long as your request is received before the close of
trading on the New York Stock Exchange, generally 4 p.m. Eastern time, you will
buy your shares at that day's net asset value. You may convert Institutional
Shares of the Institutional Index Fund into Institutional Plus Shares, or may
convert Investor Shares of any U.S. Stock Index Fund into Institutional Shares
provided that you meet the minimum initial investment requirements for such
Shares.

MINIMUM INVESTMENT TO . . .

open a new account
$10 million

add to an existing account
$100 by mail or exchange; $1,000 by wire.

BY WIRE TO OPEN A NEW ACCOUNT OR ADD TO AN EXISTING ACCOUNT [GRAPHIC]

Call your assigned Service Associate to arrange your wire transaction.

Wire to:
FRB ABA 021001088
Marine Midland Bank, New York

For credit to:
Account: 000112046
Vanguard Incoming Wire Account

In favor of:
Vanguard Institutional Index Fund - 94
Vanguard Institutional Index Fund Institutional Plus Shares - 854
Vanguard Total Stock Market Index Fund Institutional Shares - 855
Vanguard Extended Market Index Fund Institutional Shares - 856
Vanguard Mid-Cap Index Fund Institutional Shares - 864
Vanguard Small-Cap Index Fund Institutional Shares - 857
Vanguard Value Index Fund Institutional Shares - 867
Vanguard Small-Cap Value Index Fund Institutional Shares - 865
Vanguard Growth Index Fund Institutional Shares - 868
Vanguard Small-Cap Growth Index Fund Institutional Shares - 866
[Account number, or temporary number for a new account]
[Registered account owner/s]
[Registered address]

BY MAIL TO . . . [ENVELOPE GRAPHIC]
open a new account
Complete and sign the application form and enclose your check.

add to an existing account
Mail your check with an Invest-By-Mail form detached from your confirmation
statement to the address listed on the form.
<PAGE>   113
32

BUYING SHARES (continued)

Make your check payable to: The Vanguard Group (insert appropriate Fund number; 
     see below)
Vanguard Institutional Index Fund - 94
Vanguard Institutional Index Fund Institutional Plus Shares - 854
Vanguard Total Stock Market Index Fund Institutional Shares - 855
Vanguard Extended Market Index Fund Institutional Shares - 856
Vanguard Mid-Cap Index Fund Institutional Shares - 864
Vanguard Small-Cap Index Fund Institutional Shares - 857
Vanguard Value Index Fund Institutional Shares - 867
Vanguard Small-Cap Value Index Fund Institutional Shares - 865
Vanguard Growth Index Fund Institutional Shares - 868
Vanguard Small-Cap Growth Index Fund Institutional Shares - 866

All purchases must be made in U.S. dollars, and checks must be drawn on U.S.
banks.

First-class mail to:                Express or Registered mail to:
The Vanguard Group                  The Vanguard Group
P.O. Box 2900                       100 Vanguard Boulevard
Valley Forge, PA 19482-2900         Malvern, PA 19355

IMPORTANT NOTE: To prevent check fraud, Vanguard will not accept checks made
payable to third parties.

BY TELEPHONE TO . . . [TELEPHONE GRAPHIC]
open a new account
Call Vanguard Tele-Account* 24 hours a day -- or Client Services during business
hours -- to exchange from another Vanguard fund account with the same
registration (name, address, taxpayer identification number, and account type).

add to an existing account
Call Vanguard Tele-Account* 24 hours a day -- or Client Services during business
hours -- to exchange from another Vanguard fund account with the same
registration (name, address, taxpayer identification number, and account type).

Vanguard Tele-Account               Your assigned
1-800-662-6273                      Service Associate

*You must obtain a Personal Identification Number through Tele-Account at least
 seven days before you request your first exchange.

IMPORTANT NOTE: Once you've requested a telephone transaction and a confirmation
number has been assigned, the transaction cannot be revoked. We reserve the
right to refuse any purchase request.

You can redeem (that is, sell or exchange) shares purchased by check. However,
while your redemption request will be processed at the next-determined net asset
value after it is received, your redemption proceeds will not be available until
payment for your purchase is collected, which may take up to ten calendar days.

A NOTE ON LARGE PURCHASES

It is important that you call Vanguard before you invest a large dollar amount.
We must consider the interests of all Fund shareholders and so reserve the right
to refuse any purchase that will disrupt the Fund's operation or performance.

REDEEMING SHARES

This section describes how you can redeem -- that is, sell or exchange -- a
Fund's shares.

When Selling Shares:

- - Vanguard sends the redemption proceeds to you or a designated third party.*

- - You can sell all or part of your Fund shares at any time.

*Proceeds sent to third parties require a signature guarantee; see footnote on
page 34.
<PAGE>   114
                                                                              33


When Exchanging Shares:

- -  The redemption proceeds are used to purchase shares of a different Vanguard
   fund.

- -  You must meet the receiving fund's minimum investment requirements.

- -  Vanguard reserves the right to revise or terminate the exchange privilege,
   limit the amount of an exchange, or reject an exchange at any time, without
   notice.

In both cases, your transaction will be based on the Fund's next-determined
share price, subject to any special rules discussed in this prospectus. For
exchanges, the purchase side of the transaction will be based on the receiving
fund's next-determined share price, again subject to any special rules discussed
in this prospectus.

NOTE: Once a redemption is processed and a confirmation number given, the
transaction CANNOT be canceled.

HOW TO REQUEST A REDEMPTION

You can request a redemption from your Fund account in any one of two ways: by
telephone (sell, but not exchange), or by mail.

TELEPHONE REQUESTS [PHONE]

Call Vanguard Tele-Account 24 hours a day -- or Client Services during business
hours -- to sell shares.

SPECIAL INFORMATION: We will automatically establish the telephone redemption
option for your account, unless you instruct us otherwise in writing. While
telephone redemption is easy and convenient, this account feature involves a
risk of loss from unauthorized or fraudulent transactions. Vanguard will take
reasonable precautions to protect your account from fraud. You should do the
same by keeping your account information private and immediately reviewing any
account statements that we send to you. Make sure to contact Vanguard
immediately about any transaction you believe to be unauthorized.

We reserve the right to refuse a telephone redemption if the caller is unable to
provide:

   [CHECKMARK] The ten-digit account number.

   [CHECKMARK] The name and address exactly as registered on the account.

   [CHECKMARK] The primary Social Security or employer identification number as
   registered on the account.

   [CHECKMARK] The Personal Identification Number, if applicable.

  Please note that Vanguard will not be responsible for any account losses due
to telephone fraud, so long as we have taken reasonable steps to verify the
caller's identity. If you wish to remove the telephone redemption feature from
your account, please notify us in writing.

A NOTE ON UNUSUAL CIRCUMSTANCES

Vanguard reserves the right to revise or terminate the telephone redemption
privilege at any time, without notice. In addition, Vanguard can stop selling
shares or postpone payment at times when the New York Stock Exchange is closed
or under any emergency circumstances as determined by the U.S. Securities and
Exchange Commission. If you experience difficulty making a telephone redemption
during periods of drastic economic or market change, you can send us your
request by regular or express mail. Follow the instructions on selling or
exchanging shares by mail in this section.

MAIL REQUESTS [ENVELOPE]

Send a letter of instruction signed by all registered account holders. Include
the fund name and account number and (if you are selling) a dollar amount or
number of shares OR (if you are exchanging) the name of the fund you want to
exchange into and a dollar amount or number of shares. To exchange into an
account with a different registration (including a different name, address,
taxpayer identification number, or account type), you must provide Vanguard with
written instructions that include the guaranteed signatures of all current
owners of the fund from which you wish to redeem.

A NOTE ON LARGE REDEMPTIONS

It is important that you call Vanguard before you redeem a large dollar amount.
We must consider the interests of all fund shareholders and so reserve the right
to delay delivery of your redemption proceeds -- up to seven days -- if the
amount will disrupt a Fund's operation or performance.

  If you redeem more than $250,000 worth of Fund shares within any 90-day
period, the Fund reserves the right to pay part or all of the redemption
proceeds above $250,000 in kind, i.e., in securities, rather than in cash. If
payment is made in kind, you may incur brokerage commissions if you elect to
sell the securities for cash.
<PAGE>   115
34

REDEEMING SHARES (continued)

OPTIONS FOR REDEMPTION PROCEEDS

You may receive your redemption proceeds in one of two ways: check, or exchange
to another Vanguard fund.

CHECK REDEMPTIONS

Normally, Vanguard will mail your check within two business days of a
redemption.

EXCHANGE REDEMPTIONS

As described above, an exchange involves using the proceeds of your redemption
to purchase shares of another Vanguard fund.

FOR OUR MUTUAL PROTECTION

For your best interests and ours, Vanguard applies these additional requirements
to redemptions.

REQUEST IN "GOOD ORDER"

All redemption requests must be received by Vanguard in "good order." This means
that your request must include:

   [CHECKMARK] The Fund name and account number.

   [CHECKMARK] The amount of the transaction (in dollars or shares).

   [CHECKMARK] Signatures of all owners exactly as registered on the account
   (for mail requests).

   [CHECKMARK] Signature guarantees (if required).*

   [CHECKMARK] Any supporting legal documentation that may be required.

   [CHECKMARK] Any outstanding certificates representing shares to be redeemed.

*For instance, a signature guarantee must be provided by all registered account
 shareholders when redemption proceeds are to be sent to a different person or
 address. A signature guarantee can be obtained from most banks, credit unions,
 and licensed brokers.

TRANSACTIONS ARE PROCESSED AT THE NEXT-DETERMINED SHARE PRICE AFTER VANGUARD HAS
RECEIVED ALL REQUIRED INFORMATION.

LIMITS ON ACCOUNT ACTIVITY

Because excessive account transactions can disrupt management of a Fund and
increase the Fund's costs for all shareholders, Vanguard limits account activity
as follows:

- -  You may make no more than TWO SUBSTANTIVE "ROUND TRIPS" THROUGH THE FUND
   during any 12-month period.

- -  Your round trips through the Fund must be at least 30 days apart.

- -  The Fund may refuse a share purchase at any time, for any reason.

- -  Vanguard may revoke an investor's telephone exchange privilege at any time,
   for any reason.

A "round trip" is a redemption from the Fund followed by a purchase back into
the Fund. Also, "round trip" covers transactions accomplished by any combination
of methods, including transactions conducted by check, wire, or exchange to/from
another Vanguard fund. "Substantive" means a dollar amount that Vanguard
determines, in its sole discretion, could adversely affect the management of the
Fund.

ALL TRADES FINAL

Vanguard will not cancel any transaction request (including any purchase or
redemption) that we believe to be authentic once the request has been received
and a confirmation number assigned.
<PAGE>   116
                                                                              35


TRANSFERRING REGISTRATION

You can transfer the registration of your Fund shares to another owner by
completing a transfer form and sending it to Vanguard.

First-class mail to:                Express or Registered mail to:
The Vanguard Group                  The Vanguard Group
P.O. Box 2900                       455 Devon Park Drive
Valley Forge, PA 19482-2900         Wayne, PA 19087-1815

FUND AND ACCOUNT UPDATES

STATEMENTS AND REPORTS

We will send you account and tax statements to help you keep track of your Fund
account throughout the year as well as when you are preparing your income tax
returns.

  In addition, you will receive financial reports about a Fund twice a year.
These comprehensive reports include an assessment of the Fund's performance (and
a comparison to its industry benchmark), an overview of the markets, a report
from the advisers, and the Fund's financial statements which include a listing
of the Fund's holdings.

  To keep each Fund's costs as low as possible (so that you and other
shareholders can keep more of the Fund's investment earnings), Vanguard attempts
to eliminate duplicate mailings to the same address. When we find that two or
more Fund shareholders have the same last name and address, we send just one
Fund report to that address -- instead of mailing separate reports to each
shareholder. If you want us to send separate reports, however, you may notify
our Institutional Division at 1-888-809-8102.

CONFIRMATION STATEMENT

Sent each time you buy, sell, or exchange shares; confirms the trade date and
the amount of your transaction.

PORTFOLIO SUMMARY

Mailed quarterly for most accounts; shows the market value of your account at
the close of the statement period, as well as distributions, purchases, sales,
and exchanges for the current calendar year.

FUND FINANCIAL REPORTS

Mailed in February and August for all nine Funds.

TAX STATEMENTS

Generally mailed in January; report previous year's dividend and capital gains
distributions, and proceeds from the sale of shares.

MANDATORY CONVERSION TO INVESTOR SHARES

Vanguard Institutional Index Fund reserves the right to convert an investor's
Institutional Plus Shares into Institutional Shares of the Fund if the
investor's account balance falls below $200 million. The Total Stock Market,
Extended Market, Mid-Cap, Small-Cap, Value, Small-Cap Value, Growth, and
Small-Cap Growth Index Funds each reserve the right to convert an investor's
Institutional Shares into Investor Shares of the same Fund if the investor's
account balance falls below $10 million. Any such conversion will be preceded by
written notice to the investor. No fund transaction fee will be imposed on
share-class conversions.
<PAGE>   117
                      (THIS PAGE INTENTIONALLY LEFT BLANK.)


<PAGE>   118
GLOSSARY OF INVESTMENT TERMS

ACTIVE MANAGEMENT

An investment approach that seeks to exceed the average returns of the financial
markets. Active managers rely on research, market forecasts, and their own
judgment and experience in selecting securities to buy and sell.

CAPITAL GAINS DISTRIBUTION

Payment to mutual fund shareholders of gains realized on securities that the
fund has sold at a profit, minus any realized losses.

CASH RESERVES

Cash deposits, short-term bank deposits, and money market instruments which
include U.S. Treasury bills, bank certificates of deposit (CDs), repurchase
agreements, commercial paper, and banker's acceptances.

COMMON STOCK

A security representing ownership rights in a corporation. A stockholder is
entitled to share in the company's profits, some of which may be paid out as
dividends.

DIVIDEND INCOME

Payment to shareholders of income from interest or dividends generated by a
fund's investments.

DOLLAR-COST AVERAGING

Investing equal amounts of money at regular intervals on an ongoing basis. This
technique ensures that an investor buys fewer shares when prices are high and
more shares when prices are low.

EXPENSE RATIO

The percentage of a fund's average net assets used to pay its expenses. The
expense ratio includes management fees, administrative fees, and any 12b-1
distribution fees.

INDEX

An unmanaged group of securities whose overall performance is used as a standard
to measure investment performance.

INVESTMENT ADVISER

An organization that makes the day-to-day decisions regarding a fund's
investments.

MUTUAL FUND

An investment company that pools the money of many people and invests it in a
variety of securities in an effort to achieve a specific objective over time.

NET ASSET VALUE (NAV)

The market value of a mutual fund's total assets, minus liabilities, divided by
the number of shares outstanding. The value of a single share is called its
share value or share price.

PASSIVE MANAGEMENT

A low-cost investment strategy in which a mutual fund attempts to match --
rather than outperform -- a particular stock or bond market index. Also known as
indexing.

PRINCIPAL

The amount of your own money you put into an investment.

SECURITIES

Stocks, bonds, and other investment vehicles.

TOTAL RETURN

A percentage change, over a specified time period, in a mutual fund's net asset
value, with the ending net asset value adjusted to account for the reinvestment
of all distributions of dividends and capital gains.

VOLATILITY

The fluctuations in value of a mutual fund or other security. The greater a
fund's volatility, the wider the fluctuations between its high and low prices.

YIELD

Income (interest or dividends) earned by an investment, expressed as a
percentage of the investment's price.
<PAGE>   119
[THE VANGUARD GROUP LOGO]
Institutional Division
Post Office Box 2900
Valley Forge, PA 19482-2900

FOR MORE INFORMATION

If you'd like more information about Vanguard Institutional Index Fund or
Vanguard U.S. Stock Index Funds, the following documents are available free upon
request:

ANNUAL/SEMIANNUAL REPORT TO SHAREHOLDERS

Additional information about the Funds' investments is available in the Funds'
annual and semiannual reports to shareholders. In these reports, you will find a
discussion of the market conditions and investment strategies that significantly
affected the performance of the Funds during the most recent fiscal year. (The
Institutional Index Fund's reports are separate from those of the U.S. Stock
Index Funds.)

STATEMENT OF ADDITIONAL INFORMATION (SAI)

The SAI provides more information about the Funds. (The SAI for the
Institutional Index Fund is separate from that for the U.S. Stock Index Funds.)

The current annual and semiannual reports and the SAI are incorporated by
reference into (and are thus legally a part of) this prospectus.

To receive a free copy of the latest annual or semiannual report or the SAI, or
to request additional information about the Funds or other Vanguard funds,
please contact us as follows:

If you are an Individual Investor:
THE VANGUARD GROUP
INVESTOR INFORMATION DEPARTMENT
P.O. BOX 2900
VALLEY FORGE, PA 19482-2900

TELEPHONE:
1-800-662-7447 (SHIP)

TEXT TELEPHONE:
1-800-952-3335

If you are a client of Vanguard's Institutional Division:

THE VANGUARD GROUP
INSTITUTIONAL INVESTOR INFORMATION
P.O. BOX 2900
VALLEY FORGE, PA 19482-2900

TELEPHONE:
1-888-809-8102

WORLD WIDE WEB:
www.vanguard.com

If you are a current Fund shareholder and would like information about your
account, account transactions, and/or account statements, please call:

CLIENT SERVICES DEPARTMENT
TELEPHONE:

1-800-662-2739 (CREW)

TEXT TELEPHONE:
1-800-662-2738

INFORMATION PROVIDED BY THE SECURITIES AND EXCHANGE COMMISSION (SEC)

You can review and copy information about the Funds (including the SAI) at the
SEC's Public Reference Room in Washington, D.C. To find out more about this
public service, call the SEC at 1-800-SEC-0330. Reports and other information
about the Funds are also available on the SEC's website (www.sec.gov), or you
can receive copies of this information, for a fee, by writing the Public
Reference Section, Securities and Exchange Commission, Washington, DC
20549-6009.

Vanguard Institutional Index Fund's Investment Company Act file number: 811-6093

Vanguard U.S. Stock Index Funds' Investment Company Act file number: 811-2652

(C) 1999 The Vanguard Group, Inc.
All rights reserved.
Vanguard Marketing
Corporation, Distributor.

I854N - 04/26/1999
    
<PAGE>   120
 
                                     PART B
 
                              VANGUARD INDEX TRUST
   
                                 (THE "TRUST")
    
 
                      STATEMENT OF ADDITIONAL INFORMATION
 
   
                                 APRIL 26, 1999
    
 
   
     This Statement is not a prospectus but should be read in conjunction with
the Trust's current Prospectuses, as they may be amended from time to time. The
Trust's current prospectuses are dated April 26, 1999. To obtain a Prospectus or
an additional Annual Report to Shareholders, which contains the Funds' Financial
Statements as hereby incorporated by reference, please call:
    
 
                      VANGUARD INVESTOR INFORMATION CENTER
                                 1-800-662-7447
 
                               TABLE OF CONTENTS
 
   
<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
Description of the Trust....................................   B-1
Investment Policies.........................................   B-3
Fundamental Investment Limitations..........................   B-7
Purchase of Shares..........................................   B-9
Share Price.................................................   B-9
Redemption of Shares........................................  B-10
Yield and Total Return......................................  B-11
Management of the Trust.....................................  B-13
Portfolio Transactions......................................  B-17
Performance Measures........................................  B-18
Financial Statements........................................  B-19
</TABLE>
    
 
   
                            DESCRIPTION OF THE TRUST
    
 
   
ORGANIZATION
    
 
   
     The Trust was organized as a Pennsylvania business trust in 1975, and was
reorganized as a Delaware business trust in July, 1998. The Trust is registered
with the United States Securities and Exchange Commission under the Investment
Company Act of 1940 (the "1940 Act") as an open-end, diversified management
investment company. It currently offers the following funds:
    
 
   
        Vanguard 500 Index Fund
    
   
        Vanguard Total Stock Market Index Fund
    
   
        Vanguard Extended Market Index Fund
    
   
        Vanguard Mid-Cap Index Fund
    
   
        Vanguard Small-Cap Index Fund
    
   
        Vanguard Value Index Fund
    
   
        Vanguard Small-Cap Value Index Fund
    
   
        Vanguard Growth Index Fund
    
   
        Vanguard Small-Cap Growth Index Fund
    
   
        (each, a "Fund,"; collectively, the "Funds")
    
 
   
     Each of the Funds offers two classes of shares, Investor Shares and
Institutional Shares, except the 500 Index Fund, which offers Investor Shares
only. Institutional Shares of a Fund are available only to those investing at
least $10 million in the Fund.
    
 
   
     The Trust has the ability to offer additional funds or classes of shares.
There is no limit on the number of full and fractional shares that the Trust may
issue for a particular fund or class of shares.
    
 
                                       B-1
<PAGE>   121
 
   
SERVICE PROVIDERS
    
 
   
     CUSTODIANS.  State Street Bank and Trust Company, 225 Franklin Street,
Boston, Massachusetts 02110, and First Union National Bank, PA4943, 530 Walnut
Street, Philadelphia, Pennsylvania 19106, serve as the Trust's custodians. The
custodians are responsible for maintaining the Fund's assets and keeping all
necessary accounts and records.
    
 
   
     INDEPENDENT ACCOUNTANTS.  PricewaterhouseCoopers LLP, 30 South 17th Street,
Philadelphia, Pennsylvania 19103, serves as the Trust's independent accountants.
The accountants audit the Trust's financial statements and provide other related
services.
    
 
   
     TRANSFER AND DIVIDEND-PAYING AGENT.  The Fund's transfer agent and
dividend-paying agent is The Vanguard Group, Inc., 100 Vanguard Boulevard,
Malvern, Pennsylvania 19355.
    
 
   
CHARACTERISTICS OF THE TRUST'S SHARES
    
 
   
     RESTRICTIONS ON HOLDING OR DISPOSING OF SHARES.  There are no restrictions
on the right of shareholders to retain or dispose of the Trust's shares, other
than the possible future termination of the Trust or any of its funds. The Trust
or any of its funds may be terminated by reorganization into another mutual fund
or by liquidation and distribution of the assets of the affected fund. Unless
terminated by reorganization or liquidation, the Trust and its funds will
continue indefinitely.
    
 
   
     SHAREHOLDER LIABILITY.  The Trust is organized under Delaware law, which
provides that shareholders of a business trust are entitled to the same
limitations of personal liability as shareholders of a corporation organized
under Delaware law. Effectively, this means that a shareholder of the Trust will
not be personally liable for payment of the Trust's debts except by reason of
his or her own conduct or acts. In addition, a shareholder could incur a
financial loss on account of a Trust obligation only if the Trust itself had no
remaining assets with which to meet such obligation. We believe that the
possibility of such a situation arising is extremely remote.
    
 
   
     DIVIDEND RIGHTS.  The shareholders of a fund are entitled to receive any
dividends or other distributions declared for such fund. No shares have priority
or preference over any other shares of the same fund with respect to
distributions. Distributions will be made from the assets of a fund, and will be
paid ratably to all shareholders of the fund (or class) according to the number
of shares of such fund (or class) held by shareholders on the record date. The
amount of income dividends per share may vary between separate share classes of
the same fund based upon differences in the way that expenses are allocated
between share classes pursuant to a multiple class plan.
    
 
   
     VOTING RIGHTS.  Shareholders are entitled to vote on a matter if: (i) a
shareholder vote is required under the 1940 Act; (ii) the matter concerns an
amendment to the Declaration of Trust that would adversely affect to a material
degree the rights and preferences of the shares of any class or series; or (iii)
the Trustees determine that it is necessary or desirable to obtain a shareholder
vote. The 1940 Act requires a shareholder vote under various circumstances,
including to elect or remove Trustees upon the written request of shareholders
representing 10% or more of the Trust's net assets, and to change any
fundamental policy of the Trust. Shareholders of the Trust receive one vote for
each dollar of net asset value owned on the record date, and a fractional vote
for each fractional dollar of net asset value owned on the record date. However,
only the shares of the fund affected by a particular matter are entitled to vote
on that matter. Voting rights are non-cumulative and cannot be modified without
a majority vote.
    
 
   
     LIQUIDATION RIGHTS.  In the event of liquidation, shareholders will be
entitled to receive a pro rata share of the net assets of the applicable fund of
the Trust.
    
 
   
     PREEMPTIVE RIGHTS.  There are no preemptive rights associated with shares
of the Trust.
    
 
   
     CONVERSION RIGHTS.  Shareholders of the Trust may convert their shares into
another class of shares of the same series upon the satisfaction of any then
applicable eligibility requirements.
    
 
                                       B-2
<PAGE>   122
 
   
     REDEMPTION PROVISIONS.  The Trust's redemption provisions are described in
its current prospectus and elsewhere in this Statement of Additional
Information.
    
 
   
     SINKING FUND PROVISIONS.  The Trust has no sinking fund provisions.
    
 
   
     CALLS OR ASSESSMENT.  The Trust's shares, when issued, are fully paid and
non-assessable.
    
 
   
TAX STATUS OF THE TRUST
    
 
   
     Each Fund of the Trust qualifies as a "regulated investment company" under
Subchapter M of the Internal Revenue Code. This special tax status means that a
Fund will not be liable for federal tax on income and capital gains distributed
to shareholders. In order to preserve its tax status, each Fund must comply with
certain requirements. If a Fund fails to meet these requirements in any taxable
year, it will be subject to tax on its taxable income at corporate rates, and
all distributions from earnings and profits, including any distributions of net
tax-exempt income and net long-term capital gains, will be taxable to
shareholders as ordinary income. In addition, the Fund could be required to
recognize unrealized gains, pay substantial taxes and interest, and make
substantial distributions before regaining its tax status as a regulated
investment company.
    
 
   
                              INVESTMENT POLICIES
    
 
   
     REPURCHASE AGREEMENTS.  Each of the Funds that comprise the Trust may
invest in repurchase agreements with commercial banks, brokers or dealers to
generate income from its excess cash balances. A repurchase agreement is an
agreement under which a Fund acquires a fixed-income security (generally a
security issued by the U.S. Government or an agency thereof, a banker's
acceptance or a certificate of deposit) from a commercial bank, broker or
dealer, subject to resale to the seller at an agreed upon price and date
(normally, the next business day). A repurchase agreement may be considered a
loan collateralized by securities. The resale price reflects an agreed upon
interest rate effective for the period the instrument is held by the Fund and is
unrelated to the interest rate on the underlying instrument. In these
transactions, the securities acquired by the Fund (including accrued interest
earned thereon) must have a total value in excess of the value of the repurchase
agreement and are held by a custodian bank until repurchased. In addition, the
Board of Trustees will monitor the Funds' repurchase agreement transactions
generally and will establish guidelines and standards for review of the
creditworthiness of any bank, broker or dealer party to a repurchase agreement
with a Fund.
    
 
   
     The use of repurchase agreements involves certain risks. For example, if
the other party to the agreement defaults on its obligation to repurchase the
underlying security at a time when the value of the security has declined, the
Fund may incur a loss upon disposition of the security. If the other party to
the agreement becomes insolvent and subject to liquidation or reorganization
under the Bankruptcy Code or other laws, a court may determine that the
underlying security is collateral for a loan by the Fund not within the control
of the Fund and therefore the Fund may not be able to substantiate its interest
in the underlying security and may be deemed an unsecured creditor of the other
party to the agreement. While the Trust's management acknowledges these risks,
it is expected that they can be controlled through careful monitoring
procedures.
    
 
   
     LENDING OF SECURITIES.  Each Fund of the Trust may lend its securities on a
short-term or long-term basis to qualified institutional investors (typically
brokers, dealers, banks or other financial institutions) who need to borrow
securities in order to complete certain transactions, such as covering short
sales, avoiding failures to deliver securities or completing arbitrage
operations. By lending its portfolio securities, a Fund attempts to increase its
net investment income through the receipt of interest on the loan. Any gain or
loss in the market price of the securities loaned that might occur during the
term of the loan would be for the account of the Fund. The terms, the structure
and the aggregate amount of such loans must be consistent with the Investment
Company Act of 1940, and the Rules and Regulations or interpretations of the
Securities and Exchange Commission (the "Commission") thereunder. These
provisions limit the amount of securities a fund may lend to 33 1/3% of the
Fund's total assets, and require that (a) the borrower pledge and maintain with
the Fund collateral consisting of cash, a letter of credit issued by a domestic
U.S. bank, or securities issued or
    
 
                                       B-3
<PAGE>   123
 
   
guaranteed by the United States Government having at all times not less than
100% of the value of the securities loaned, (b) the borrower add to such
collateral whenever the price of the securities loaned rises (i.e., the borrower
"marks to the market" on a daily basis), (c) the loan be made subject to
termination by the Fund at any time and (d) the Fund receive reasonable interest
on the loan (which may include the Fund's investing any cash collateral in
interest bearing short-term investments), any distribution on the loaned
securities and any increase in their market value. Loan arrangements made by the
Fund will comply with all other applicable regulatory requirements, including
the rules of the New York Stock Exchange, which rules presently require the
borrower, after notice, to redeliver the securities within the normal settlement
time of three business days. All relevant facts and circumstances, including the
creditworthiness of the broker, dealer or institution, will be considered in
making decisions with respect to the lending of securities, subject to review by
the Board of Trustees.
    
 
     At the present time, the Staff of the Commission does not object if an
investment company pays reasonable negotiated fees in connection with loaned
securities, so long as such fees are set forth in a written contract and
approved by the investment company's trustees. In addition, voting rights pass
with the loaned securities, but if a material event will occur affecting an
investment on loan, the loan must be called and the securities voted.
 
   
     VANGUARD INTERFUND LENDING PROGRAM.  The SEC has issued an exemptive order
permitting the Funds to participate in Vanguard's interfund lending program.
This program allows the Vanguard funds to borrow money from and loan money to
each other for temporary or emergency purposes. The program is subject to a
number of conditions, including the requirement that no fund may borrow or lend
money through the program unless it receives a more favorable interest rate than
is available from a typical bank for a comparable transaction. In addition, a
fund may participate in the program only if and to the extent that such
participation is consistent with the fund's investment objective and other
investment policies. The Boards of Trustees of the Vanguard funds are
responsible for ensuring that the interfund lending program operates in
compliance with all conditions of the SEC's exemptive order.
    
 
   
     ILLIQUID SECURITIES.  Each Fund may invest up to 15% of its net assets in
illiquid securities. Illiquid securities are securities that the Fund may not be
able to sell or dispose of in the ordinary course of business within seven
business days at approximately the value at which they are being carried on the
Fund's books.
    
 
   
     FUTURES CONTRACTS.  Each Fund of the Trust may enter into futures
contracts, options, warrants, options on futures contracts, convertible
securities and swap agreements for the purpose of simulating full investment and
reducing transactions costs. The Trust does not use futures or options for
speculative purposes. Each Fund will only use futures and options to simulate
full investment in the underlying index while retaining a cash balance for fund
management purposes. Futures contracts provide for the future sale by one party
and purchase by another party of a specified amount of a specific security at a
specified future time and at a specified price. Futures contracts which are
standardized as to maturity date and underlying financial instrument are traded
on national futures exchanges. Futures exchanges and trading are regulated under
the Commodity Exchange Act by the Commodity Futures Trading Commission ("CFTC"),
a U.S. Government agency. Assets committed to futures contracts will be
segregated to the extent required by law.
    
 
     Although futures contracts by their terms call for actual delivery or
acceptance of the underlying securities, in most cases the contracts are closed
out before the settlement date without the making or taking of delivery. Closing
out an open futures position is done by taking an opposite position ("buying" a
contract which has previously been "sold," or "selling" a contract previously
purchased) in an identical contract to terminate the position. Brokerage
commissions are incurred when a futures contract is bought or sold.
 
     Futures traders are required to make a good faith margin deposit in cash or
government securities with a broker or custodian to initiate and maintain open
positions in futures contracts. A margin deposit is intended to assure
completion of the contract (delivery or acceptance of the underlying security)
if it is not terminated prior to the specified delivery date. Minimal initial
margin requirements are established by the futures exchange and may be changed.
Brokers may establish deposit requirements which are higher than the exchange
minimums. Futures contracts are customarily purchased and sold on deposits which
may range upward from less than 5% of the value of the contract being traded.
                                       B-4
<PAGE>   124
 
   
     After a futures contract position is opened, the value of the contract is
marked to market daily. If the futures contract price changes to the extent that
the margin on deposit does not satisfy margin requirements, payment of
additional "variation" margin will be required. Conversely, change in the
contract value may reduce the required margin, resulting in a repayment of
excess margin to the contract holder. Variation margin payments are made to and
from the futures broker for as long as the contract remains open. Each Fund of
the Trust expects to earn interest income on its margin deposits.
    
 
   
     Traders in futures contracts may be broadly classified as either "hedgers"
or "speculators." Hedgers use the futures markets primarily to offset
unfavorable changes in the value of securities either held for investment
purposes or expected to be acquired by them. Speculators are less inclined to
own, or intend to purchase, the securities underlying the futures contracts
which they trade, and use futures contracts with the expectation of realizing
profits from fluctuations in the prices of underlying securities. The Trust's
Funds intend to use futures contracts only for bona fide hedging purposes.
    
 
   
     Regulations of the CFTC applicable to the Fund require that all of its
futures transactions constitute bona fide hedging transactions except to the
extent that the aggregate initial margins and premiums required to establish any
non-hedging positions do not exceed five percent of the value of any Fund's
portfolio. A Fund will only sell futures contracts to protect the Fund against
declines in the prices of the securities underlying the futures contracts or
purchase contracts to protect against an increase in the price of securities it
intends to purchase. As evidence of this hedging interest, the Fund expects that
the majority of its futures contract purchases will be "completed;" that is,
equivalent amounts of related securities will have been purchased or are being
purchased by the Fund upon sale of open futures contracts.
    
 
   
     Although techniques other than the sale and purchase of futures contracts
could be used to control a Fund's exposure to market fluctuations, the use of
futures contracts may be a more effective means of hedging this exposure. While
a Fund will incur commission expenses in both opening and closing out futures
positions, these costs are lower than transaction costs incurred in the purchase
and sale of the underlying securities.
    
 
   
     RESTRICTIONS ON THE USE OF FUTURES CONTRACTS.  A Fund will not enter into
futures contract transactions to the extent that, immediately thereafter, the
sum of its initial margin deposits on open contracts exceeds 5% of the market
value of the Fund's total assets. In addition, a Fund will not enter into
futures contracts to the extent that its outstanding obligations to purchase
securities under these contracts would exceed 20% of the Fund's total assets.
    
 
   
     RISK FACTORS IN FUTURES TRANSACTIONS.  Positions in futures contracts may
be closed out only on an Exchange which provides a secondary market for such
futures. However, there can be no assurance that a liquid secondary market will
exist for any particular futures contract at any specific time. Thus, it may not
be possible to close a futures position. In the event of adverse price
movements, a Fund would continue to be required to make daily cash payments to
maintain its required margin. In such situations, if a Fund has insufficient
cash, it may have to sell portfolio securities to meet daily margin requirements
at a time when it may be disadvantageous to do so. In addition, a Fund may be
required to make delivery of the instruments underlying futures contracts it
holds. The inability to close options and futures positions also could have an
adverse impact on the ability to effectively hedge.
    
 
   
     Each Fund will minimize the risk that it will be unable to close out a
futures contract by only entering into futures which are traded on national
futures exchanges and for which there appears to be a liquid secondary market.
    
 
     The risk of loss in trading futures contracts in some strategies can be
substantial, due both to the low margin deposits required, and the extremely
high degree of leverage involved in futures pricing. As a result, a relatively
small price movement in a futures contract may result in immediate and
substantial loss (as well as gain) to the investor. For example, if at the time
of purchase, 10% of the value of the futures contract is deposited as margin, a
subsequent 10% decrease in the value of the futures contract would result in a
total loss of the margin deposit, before any deduction for the transaction
costs, if the account were then closed out. A 15% decrease would result in a
loss equal to 150% of the original margin deposit if the contract were closed
 
                                       B-5
<PAGE>   125
 
   
out. Thus, a purchase or sale of a futures contract may result in losses in
excess of the amount invested in the contract. The Funds also bear the risk that
the adviser will incorrectly predict future stock market trends. However,
because the futures strategy of the Funds is engaged in only for hedging
purposes, the Funds' Officers do not believe that the Funds are subject to the
risks of loss frequently associated with futures transactions. A Fund would
presumably have sustained comparable losses if, instead of the futures contract,
it had invested in the underlying financial instrument and sold it after the
decline.
    
 
   
     Utilization of futures transactions by a Fund does involve the risk of
imperfect or no correlation where the securities underlying futures contracts
have different maturities than the portfolio securities being hedged. It is also
possible that a Fund could both lose money on futures contracts and also
experience a decline in value of its portfolio securities. There is also the
risk of loss by a Fund of margin deposits in the event of bankruptcy of a broker
with whom the Fund has an open position in a futures contract or related option.
    
 
     Most futures exchanges limit the amount of fluctuation permitted in futures
contract prices during a single trading day. The daily limit establishes the
maximum amount that the price of a futures contract may vary either up or down
from the previous day's settlement price at the end of a trading session. Once
the daily limit has been reached in a particular type of contract, no trades may
be made on that day at a price beyond that limit. The daily limit governs only
price movement during a particular trading day and therefore does not limit
potential losses, because the limit may prevent the liquidation of unfavorable
positions. Futures contract prices have occasionally moved to the daily limit
for several consecutive trading days with little or no trading, thereby
preventing prompt liquidation of future positions and subjecting some futures
traders to substantial losses.
 
   
     FEDERAL TAX TREATMENT OF FUTURES CONTRACTS.  Each Fund of the Trust is
required for federal income tax purposes to recognize as income for each taxable
year its net unrealized gains and losses on certain futures contracts as of the
end of the year as well as those actually realized during the year. In most
cases, any gain or loss recognized with respect to a futures contract is
considered to be 60% long-term capital gain or loss and 40% short-term capital
gain or loss, without regard to the holding period of the contract. Furthermore,
sales of futures contracts which are intended to hedge against a change in the
value of securities held by a Fund may affect the holding period of such
securities and, consequently, the nature of the gain or loss on such securities
upon disposition. A Fund may be required to defer the recognition of losses on
futures contracts to the extent of any unrecognized gains on related positions
held by the Fund.
    
 
   
     In order for each Fund to continue to qualify for Federal income tax
treatment as a regulated investment company, at least 90% of its gross income
for a taxable year must be derived from qualifying income; i.e., dividends,
interest, income derived from loans of securities, gains from the sale of
securities or of foreign currencies or other income derived with respect to the
Fund's business of investing in securities. Net gain realized from the closing
out of futures contracts will be considered qualifying income for purposes of
the 90% requirement.
    
 
   
     Each Fund will distribute to shareholders annually any net capital gains
which have been recognized for federal income tax purposes (including unrealized
gains at the end of the Fund's fiscal year) on futures transactions. Such
distributions will be combined with distributions of capital gains realized on
the Fund's other investments and shareholders will be advised on the nature of
the distributions.
    
 
   
     FOREIGN INVESTMENTS.  Each Fund may invest in foreign securities to the
extent necessary to carry out its investment strategy of holding all, or a
representative sample, of the stocks that comprise the index it tracks.
Investors should recognize that investing in foreign companies involves certain
special considerations which are not typically associated with investing in U.S.
companies.
    
 
   
     CURRENCY RISK.  Since the stocks of foreign companies are frequently
denominated in foreign currencies, and since the Funds may temporarily hold
uninvested reserves in bank deposits in foreign currencies, the Funds will be
affected favorably or unfavorably by changes in currency rates and in exchange
control regulations, and may incur costs in connection with conversions between
various currencies. The investment policies of the Funds permit them to enter
into forward foreign currency exchange contracts in order to hedge a Fund's
holdings and commitments against changes in the level of future currency rates.
Such contracts
    
 
                                       B-6
<PAGE>   126
 
   
involve an obligation to purchase or sell a specific currency at a future date
at a price set at the time of the contract.
    
 
   
     FEDERAL TAX TREATMENT OF NON-U.S. TRANSACTIONS.  Special rules govern the
Federal income tax treatment of certain transactions denominated in terms of a
currency other than the U.S. dollar or determined by reference to the value of
one or more currencies other than the U.S. dollar. The types of transactions
covered by the special rules include the following: (1) the acquisition of, or
becoming the obligor under, a bond or other debt instrument (including, to the
extent provided in Treasury regulations, preferred stock); (ii) the accruing of
certain trade receivables and payables; and (iii) the entering into or
acquisition of any forward contract, futures contract, option and similar
financial instrument if such instrument is not marked to market. The disposition
of a currency other than the U.S. dollar by a U.S. taxpayer is also treated as a
transaction subject to the special currency rules. However, foreign
currency-related regulated futures contracts and nonequity options are generally
not subject to the special currency rules if they are or would be treated as
sold for their fair market value at year-end under the marking-to-market rules
applicable to other futures contracts unless an election is made to have such
currency rules apply. With respect to transactions covered by the special rules,
foreign currency gain or loss is calculated separately from any gain or loss on
the underlying transaction and is normally taxable as ordinary gain or loss. A
taxpayer may elect to treat as capital gain or loss foreign currency gain or
loss arising from certain identified forward contracts, futures contracts and
options that are capital assets in the hands of the taxpayer and which are not
part of a straddle. The Treasury Department issued regulations under which
certain transactions subject to the special currency rules that are part of a
"section 988 hedging transaction" (as defined in the Internal Revenue Code of
1986, as amended, and the Treasury regulations) will be integrated and treated
as a single transaction or otherwise treated consistently for purposes of the
Code. Any gain or loss attributable to the foreign currency component of a
transaction engaged in by a Fund which is not subject to the special currency
rules (such as foreign equity investments other than certain preferred stocks)
will be treated as capital gain or loss and will not be segregated from the gain
or loss on the underlying transaction. It is anticipated that some of the
non-U.S. dollar-denominated investments and foreign currency contracts the Fund
may make or enter into will be subject to the special currency rules described
above.
    
 
   
     COUNTRY RISK.  As foreign companies are not generally subject to uniform
accounting, auditing and financial reporting standards and practices comparable
to those applicable to domestic companies, there may be less publicly available
information about certain foreign companies than about domestic companies.
Securities of some foreign companies are generally less liquid and more volatile
than securities of comparable domestic companies. There is generally less
government supervision and regulation of stock exchanges, brokers and listed
companies than in the U.S. In addition, with respect to certain foreign
countries, there is the possibility of expropriation of confiscatory taxation,
political or social instability, or diplomatic developments which could affect
U.S. investments in those countries.
    
 
   
     Although the Funds will endeavor to achieve most favorable execution costs
in their portfolio transactions, fixed commissions on many foreign stock
exchanges are generally higher than negotiated commissions on U.S. exchanges. In
addition, it is expected that the expenses for custodian arrangements of the
Funds' foreign securities will be somewhat greater than the expenses for the
custodian arrangements for handling U.S. securities of equal value.
    
 
   
     Certain foreign governments levy withholding taxes against dividend and
interest income. Although in some countries a portion of these taxes is
recoverable, the non-recovered portion of foreign withholding taxes will reduce
the income received from foreign companies held by the Funds. However, these
foreign withholding taxes are not expected to have a significant impact on the
Funds, since each Fund seeks long-term capital appreciation and any income
should be considered incidental.
    
 
   
                       FUNDAMENTAL INVESTMENT LIMITATIONS
    
 
   
     Each Fund of the Trust is subject to the following fundamental investment
limitations, which cannot be changed in any material way without the approval of
the holders of a majority of the Fund's shares. For these purposes, a "majority"
of shares means the lesser of: (i) 67% or more of the votes cast to approve a
change, so
    
                                       B-7
<PAGE>   127
 
   
long as shares representing more than 50% of a Fund's net asset value are
present or represented by proxy; or (ii) shares representing more than 50% of a
Fund's net asset value.
    
 
   
     BORROWING.  A Fund may not borrow money, except for temporary or emergency
purposes in an amount not exceeding 15% of the Fund's net assets. A Fund may
borrow money through banks, reverse repurchase agreements, or Vanguard's
interfund lending program only, and must comply with all applicable regulatory
conditions. A Fund may not make any additional investments if its outstanding
borrowings exceed 5% of net assets.
    
 
   
     COMMODITIES.  A Fund may not invest in commodities, except that it may
invest in stock index futures contracts, stock options and options on stock
index futures contracts. No more than 5% of a Fund's assets may be used as
initial margin deposit for futures contracts, and no more than 20% of a Fund's
assets may be invested in futures contracts or options at any time.
    
 
   
     DIVERSIFICATION.  With respect to 75% of its total assets, a Fund may not:
(i) purchase more than 10% of the outstanding voting securities of any one
issuer; or (ii) 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. This
limitation does not apply to obligations of the United States Government, its
agencies, or instrumentalities.
    
 
   
     ILLIQUID SECURITIES.  A Fund may not acquire any security if, as a result,
more than 15% of its net assets would be invested in securities that are
illiquid. From time to time, the Trust's Board of Trustees may determine that
certain restricted securities known as Rule 144A securities are liquid and not
subject to the 15% limitation.
    
 
   
     INDUSTRY CONCENTRATION.  A Fund may not invest more than 25% of its total
assets in any one industry.
    
 
   
     INVESTING FOR CONTROL.  A Fund may not invest in a company for purposes of
controlling its management.
    
 
   
     INVESTMENT COMPANIES.  A Fund may not invest in any other investment
company, except through a merger, consolidation or acquisition of assets, or to
the extent permitted by Section 12 of the 1940 Act. Investment companies whose
shares a Fund acquires pursuant to Section 12 must have investment objectives
and investment policies consistent with those of the Fund.
    
 
   
     LOANS.  A Fund may not lend money to any person except by purchasing fixed
income securities that are publicly distributed, lending its portfolio
securities, or through Vanguard's interfund lending program.
    
 
   
     MARGIN.  A Fund may not purchase securities on margin or sell securities
short, except as permitted by the Fund's investment policies relating to
commodities.
    
 
   
     OIL, GAS, MINERALS.  A Fund may not invest in interests in oil, gas or
other mineral exploration or development programs.
    
 
   
     PLEDGING ASSETS.  A Fund may not pledge, mortgage or hypothecate more than
15% of its net assets.
    
 
   
     REAL ESTATE.  A Fund may not invest directly in real estate, although it
may invest in securities of companies that deal in real estate.
    
 
   
     SENIOR SECURITIES.  A Fund may not issue senior securities, except in
compliance with the 1940 Act.
    
 
   
     UNDERWRITING.  A Fund may not engage in the business of underwriting
securities issued by other persons. The Fund will not be considered an
underwriter when disposing of its investment securities.
    
 
   
     WARRANTS.  A Fund may not purchase or sell warrants, put options or call
options.
    
 
   
     The above-mentioned investment limitations are considered at the time
investment securities are purchased.
    
 
   
     None of these limitations prevents the Trust from participating in The
Vanguard Group ("Vanguard"). Because the Trust is a member of the Group, the
Funds may own securities issued by Vanguard, make loans to Vanguard, and
contribute to Vanguard's costs or other financial requirement. See "Management
of the Trust" for more information.
    
 
                                       B-8
<PAGE>   128
 
   
                               PURCHASE OF SHARES
    
 
   
     The Trust reserves the right in its sole discretion (i) to suspend the
offerings of a Fund's shares, (ii) to reject purchase or exchange purchase
orders when in the judgment of management such rejection is in the best interest
of a Fund, and (iii) to reduce or waive the minimum investment for, or any other
restrictions on, initial and subsequent investments as well as redemption fees
for certain fiduciary accounts or under circumstances where certain economies
can be achieved in sales of a Fund's shares.
    
 
   
     EXCHANGE OF SECURITIES FOR SHARES OF A FUND.  In certain circumstances,
shares of a Fund may be purchased "in kind," i.e., in exchange for securities,
rather than for cash. The securities tendered as part of an in-kind purchase
must be included in the Index tracked by the Fund and must have a total market
value of $1 million or more. In addition, each position must have a market value
of $10,000 or more. Such securities also must be liquid securities which are not
restricted as to transfer and have a value that is readily ascertainable as
evidenced by a listing on the American Stock Exchange, the New York Stock
Exchange or NASDAQ. Securities accepted by the Fund will be valued as set forth
under "Share Price" in the Trust's prospectus as of the time of the next
determination of net asset value after such acceptance. Shares of each Fund are
issued at net asset value determined as of the same time. "IN-KIND" PURCHASES OF
THE SMALL-CAP INDEX, EXTENDED MARKET INDEX, MID-CAP INDEX, SMALL-CAP VALUE
INDEX, AND SMALL-CAP GROWTH INDEX FUNDS WILL NOT BE SUBJECT TO THEIR NORMAL
TRANSACTION FEES, 0.5%, 0.25%, 0.25%, 1.00% AND 1.00%, RESPECTIVELY. All
dividend, subscription, or other rights that are reflected in the market price
of accepted securities at the time of valuation become the property of the Fund
and must be delivered to the Fund by the investor upon receipt from the issuer.
A gain or loss for Federal income tax purposes would be realized by the investor
upon the exchange depending upon the cost of the securities tendered.
    
 
   
     A Fund will not accept securities in exchange for its shares unless: (1)
such securities are, at the time of the exchange, held by the Fund; (2) the
transaction will not cause the Fund's weightings to become imbalanced with
respect to the weightings of the stocks included in the corresponding Index; (3)
the investor represents and agrees that all securities offered to the Fund are
not subject to any restrictions upon their sale by the Fund under the Securities
Act of 1933, or otherwise; (4) such securities are traded in an unrelated
transaction with a quoted sales price on the same day the exchange valuation is
made; (5) the quoted sales price used as a basis of valuation is representative
(e.g., one that does not involve a trade of substantial size that artificially
influences the price of the security); and (6) the value of any such security
being exchanged will not exceed 5% of the Fund's net assets immediately prior to
the transaction.
    
 
   
     Investors interested in purchasing Fund shares with securities should
contact Vanguard.
    
 
                                  SHARE PRICE
 
   
     The share price, or "net asset value" per share for the 500 Index Fund is
calculated by dividing the total assets of the Fund, less all liabilities, by
the total number of shares outstanding. The net asset value for each share class
of the other Funds that comprise the Trust are calculated by dividing the net
assets attributable to each share class by the total number of shares
outstanding for that share class. The net asset value is determined as of the
close of the New York Stock Exchange (generally 4:00 p.m. Eastern time) on each
day the Exchange is open for trading.
    
 
     Portfolio securities for which market quotations are readily available
(includes those securities listed on national securities exchanges, as well as
those quoted on the NASDAQ Stock Market) will be valued at the last quoted sales
price on the day the valuation is made. Such securities which are not traded on
the valuation date are valued at the mean of the bid and ask prices. Price
information on exchange-listed securities is taken from the exchange where the
security is primarily traded. Securities may be valued on the basis of prices
provided by a pricing service when such prices are believed to reflect the fair
market value of such securities.
 
   
     Short-term instruments (those acquired with remaining maturities of 60 days
or less) may be valued at cost, plus or minus any amortized discount or premium,
which approximates market value.
    
 
     Bonds and other fixed income securities may be valued on the basis of
prices provided by a pricing service when such prices are believed to reflect
the fair market value of such securities. The prices provided by a
 
                                       B-9
<PAGE>   129
 
pricing service may be determined without regard to bid or last sale prices of
each security, but take into account institutional-size transactions in similar
groups of securities as well as any developments related to specific securities.
 
   
     Foreign securities are valued at the last quoted sales price, according to
the broadest and most representative market, available at the time a Fund is
valued. If events which materially affect the value of a Fund's investments
occur after the close of the securities markets on which such securities are
primarily traded, those investments may be valued by such methods as the Board
of Trustees deems in good faith to reflect fair value.
    
 
   
     In determining a Fund's net asset value per share, all assets and
liabilities initially expressed in foreign currencies will be converted into
U.S. dollars using the officially quoted daily exchange rates used by Morgan
Stanley Capital International in calculating various benchmarking indices. This
officially quoted exchange rate may be determined prior to or after the close of
a particular securities market. If such quotations are not available, the rate
of exchange will be determined in accordance with policies established in good
faith by the Board of Trustees.
    
 
     Other assets and securities for which no quotations are readily available
or which are restricted as to sale (or resale) are valued by such methods as the
Board of Trustees deems in good faith to reflect fair value.
 
   
     The share price for each Fund can be found daily in the mutual fund
listings of most major newspapers under the heading of Vanguard Index Funds.
    
 
                              REDEMPTION OF SHARES
 
   
     Each Fund may suspend redemption privileges or postpone the date of payment
(i) during any period that the New York Stock Exchange is closed, or trading on
the Exchange is restricted as determined by the Securities and Exchange
Commission (the "Commission"), (ii) during any period when an emergency exists
as defined by the rules of the Commission as a result of which it is not
reasonably practicable for the Trust to dispose of securities owned by it, or
fairly to determine the value of its assets, and (iii) for such other periods as
the Commission may permit.
    
 
   
     No charge is made by a Fund for redemptions. The proceeds of a redemption
may be more or less than the shareholder's cost depending on the market value of
the securities held by the Fund.
    
 
   
     The Trust has authorized Charles Schwab & Co., Inc. ("Schwab") to accept on
its behalf purchase and redemption orders under certain terms and conditions.
Schwab is also authorized to designate other intermediaries to accept purchase
and redemption orders on the Trust's behalf subject to those terms and
conditions. Under this arrangement, the Trust will be deemed to have received a
purchase or redemption order when Schwab or, if applicable, Schwab's authorized
designee, accepts the order in accordance with the Trust's instructions.
Customer orders that are properly transmitted to the Trust by Schwab, or if
applicable, Schwab's authorized designee, will be priced as follows:
    
 
     If you place your order through Schwab and it is received before 3 p.m.
Eastern time on any business day, your order will be sent to Vanguard that day
and your share price will be based on the Trust's net asset value calculated at
the close of trading that day. If your order is received after 3 p.m. Eastern
time, it will be sent to Vanguard on the following business day and your share
price will be based on the Trust's net asset value calculated at the close of
trading that day.
 
                                      B-10
<PAGE>   130
 
   
                             YIELD AND TOTAL RETURN
    
 
   
     The annualized yield of each Fund of the Trust for the 30-day period ended
December 31, 1998 is set forth below.
    
 
   
<TABLE>
<CAPTION>
                                                              INVESTOR    INSTITUTIONAL
                                                               SHARES        SHARES
                                                              --------    -------------
<S>                                                           <C>         <C>
500 Index Fund..............................................    --%            N/A
Total Stock Market Index Fund...............................    --              --%
Extended Market Index Fund..................................    --              --
Mid-Cap Index Fund..........................................    --              --
Small-Cap Index Fund........................................    --              --
Value Index Fund............................................    --              --
Small-Cap Value Index Fund..................................    --              --
Growth Index Fund...........................................    --              --
Small-Cap Growth Index Fund.................................    --              --
</TABLE>
    
 
   
     The average annual total return of each Fund of the Trust for the one-,
five-, and ten-year periods ended December 31, 1998 is set forth below.
    
 
   
<TABLE>
<CAPTION>
                                                                            5 YEARS         10 YEARS
                                                          1 YEAR ENDED       ENDED            ENDED
INVESTOR SHARES                                            12/31/1998      12/31/1998      12/31/1998
- ---------------                                           ------------    ------------    -------------
<S>                                                       <C>             <C>             <C>
500 Index Fund*.........................................     --%             --%              --%
Total Stock Market Index Fund*..........................      --              --               --(1)+
Extended Market Index Fund**............................      --              --               --
Small-Cap Index Fund***.................................      --              --               --
Value Index Fund*.......................................      --              --               --(2)+
Growth Index Fund*......................................      --              --               --(3)+
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                        1 YEAR ENDED    5 YEARS ENDED    10 YEARS ENDED
                 INSTITUTIONAL SHARES                    12/31/1998      12/31/1998        12/31/1998
                 --------------------                   ------------    -------------    --------------
<S>                                                     <C>             <C>              <C>
Total Stock Market Index Fund.........................      --%              --%(4)+          --
Extended Market Index Fund............................      --               --(4)+           --
Small-Cap Index Fund..................................      --               --(4)+           --
</TABLE>
    
 
- ---------------
   
  * Total return figures are not adjusted to reflect the $10 annual account
    maintenance fee.
    
   
 ** Total return figures for the Extended Market Index Fund are not adjusted to
    reflect the 0.25% portfolio transaction fee and the $10 annual account
    maintenance fee.
    
   
*** Total return figures for the Small-Cap Index Fund are not adjusted to
    reflect the 0.5% portfolio transaction fee and the $10 annual account
    maintenance fee.
    
   
 + Annualized.
    
   
 (1) Since the inception date of the Total Stock Market Index Fund on March 16,
1992.
    
   
 (2) Since the inception date of the Value Index Fund on November 2, 1992.
    
   
 (3) Since the inception date of the Growth Index Fund on November 2, 1992.
    
   
 (4) Since the inception date of the Institutional Shares of the Fund on July 7,
1997.
    
 
   
     The Investor Shares and the Institutional Shares of the Mid-Cap Index Fund,
Small-Cap Value Index Fund, and Small-Cap Growth Index Fund were not offered
prior to April 20, 1998. The Institutional Shares of the Value Index Fund and
the Growth Index Fund were not offered prior to April 20, 1998.
    
 
   
AVERAGE ANNUAL TOTAL RETURN
    
 
   
     Average annual total return is the average annual compounded rate of return
for the periods of one year, five years, ten years or the life of the Fund, all
ended on the last day of a recent month. Average annual total return quotations
reflect changes in the price of the Fund's shares and assume that all dividends
and capital gains distributions during the respective periods were reinvested in
Fund shares. Average annual total return is calculated by finding the average
annual compounded rates of return of a hypothetical investment over
    
                                      B-11
<PAGE>   131
 
   
such periods according to the following formula (average annual total return is
then expressed as a percentage):
    
 
   
                                T = (ERV/P)1/n-1
    
 
   
<TABLE>
<S>          <C>    <C>
 
     Where:  T = average annual total return
             P = a hypothetical initial payment of $1,000
             n = number of years
             ERV = ending redeemable value: ERV is the value, at the end of the
             applicable period, of a hypothetical $1,000 investment made at the
                   beginning of the applicable period.
</TABLE>
    
 
   
CUMULATIVE TOTAL RETURN
    
 
   
     Cumulative total return is the cumulative rate of return on a hypothetical
initial investment of $1,000 for a specified period. Cumulative total return
quotations reflect changes in the price of the Fund's shares and assume that all
dividends and capital gains distributions during the period were reinvested in
Fund shares. Cumulative total return is calculated by finding the cumulative
rates of a return of a hypothetical investment over such periods, according to
the following formula (cumulative total return is then expressed as a
percentage):
    
 
   
                                 C = (ERV/P)-1
    
 
   
<TABLE>
<S>          <C>    <C>
 
     Where:  C = cumulative total return
             P = a hypothetical initial payment of $1,000
             ERV = ending redeemable value: ERV is the value, at the end of the
             applicable period, of a hypothetical $1,000 investment made at the
                   beginning of the applicable period.
</TABLE>
    
 
   
SEC YIELDS
    
 
   
     Yield is the net annualized yield based on the specified 30-day (or one
month) period assuming semiannual compounding of income. Yield is calculated by
dividing the net investment income per share earned during the period by the
maximum offering price per share on the last day of the period, according to the
following formula:
    
 
   
                        Yield = 2[((a-b)/(cXd)+1)(6)-1]
    
   
    
 
   
<TABLE>
    <C>          <S>
 
       Where:    a = dividends and interest earned during the period.
                 b = expense accrued for the period (net of reimbursements).
 
                 c = the average daily number of shares outstanding during
                 the period that were entitled to receive dividends.
 
                 d = the maximum offering price per share on the last day of
                 the period.
</TABLE>
    
 
                                      B-12
<PAGE>   132
 
                            MANAGEMENT OF THE TRUST
 
   
OFFICERS AND TRUSTEES
    
 
   
     The Officers of the Trust manage its day-to-day operations and are
responsible to the Trust's Board of Trustees. The Trustees set broad policies
for the Trust and choose its Officers. The following is a list of the Trustees
and Officers of the Trust and a statement of their present positions and
principal occupations during the past five years. As a group, the Trust's
Trustees and Officers own less than 1% of the outstanding shares of each Fund of
the Trust. Each Trustee also serves as a Director of the Vanguard Group, Inc.,
and as a Trustee of each of the 36 investment companies administered by Vanguard
(35 in the case of Mr. Malkiel and 28 in the case of Mr. MacLaury). The mailing
address of the Trustees and Officers of the Trust is Post Office Box 876, Valley
Forge, PA 19482.
    
 
   
JOHN C. BOGLE, (DOB: 5/8/1929) Senior Chairman and Trustee*
    
   
Senior Chairman and Director of The Vanguard Group, Inc., and Trustee of each of
the investment companies in The Vanguard Group; Director of The Mead Corp.
(Paper Products), General Accident Insurance, and Chris-Craft Industries, Inc.
(Broadcasting & Plastics Manufacturer).
    
 
   
JOHN J. BRENNAN, (DOB: 7/29/1954) Chairman, Chief Executive Officer & Trustee*
    
   
Chairman, Chief Executive Officer and Director of The Vanguard Group, Inc., and
Trustee of each of the investment companies in The Vanguard Group.
    
 
   
JOANN HEFFERNAN HEISEN, (DOB: 1/25/1950) Trustee
    
   
Vice President, Chief Information Officer, and member of the Executive Committee
of Johnson and Johnson (Pharmaceuticals/Consumer Products), Director of Johnson
& Johnson*MERCK Consumer Pharmaceuticals Co., Women First HealthCare, Inc.
(Research and Education Institution), Recording for the Blind and Dyslexic, The
Medical Center at Princeton, and Women's Research and Education Institute.
    
 
   
BRUCE K. MACLAURY, (DOB: 5/7/1931) Trustee
    
   
President Emeritus of The Brookings Institution (Independent Non-Partisan
Research Organization); Director of American Express Bank, Ltd., The St. Paul
Companies, Inc. (Insurance and Financial Services), and National Steel Corp.
    
 
   
BURTON G. MALKIEL, (DOB: 8/28/1932) Trustee
    
   
Chemical Bank Chairman's Professor of Economics, Princeton University; Director
of Prudential Insurance Co. of America, Banco Bilbao Gestinova, Baker Fentress &
Co. (Investment Management), The Jeffrey Co. (Holding Company), and Southern New
England Telecommunications Co.
    
 
   
ALFRED M. RANKIN, JR., (DOB: 10/8/1941) Trustee
    
   
Chairman, President, Chief Executive Officer, and Director of NACCO Industries
(Machinery/Coal/Appliances); Director of The BFGoodrich Co. (Aircraft
Systems/Manufacturing/Chemicals), and The Standard Products Co. (Rubber Products
Company).
    
 
   
JOHN C. SAWHILL, (DOB: 6/12/1936) Trustee
    
   
President and Chief Executive Officer of The Nature Conservancy (Non-Profit
Conservation Group); Director of Pacific Gas and Electric Co., Procter & Gamble
Co., NACCO Industries (Machinery/Coal/Appliances), and Newfield Exploration Co.
(Energy); formerly, Director and Senior Partner of McKinsey & Co., and President
of New York University.
    
 
   
JAMES O. WELCH, JR., (DOB: 5/13/1931) Trustee
    
   
Retired Chairman of Nabisco Brands, Inc. (Food Products); retired Vice Chairman
and Director of RJR Nabisco (Food and Tobacco Products); Director of TECO
Energy, Inc., and Kmart Corp.
    
 
   
J. LAWRENCE WILSON, (DOB: 3/2/1936) Trustee
    
   
Chairman and Chief Executive Officer of Rohm & Haas Co. (Chemicals); Director of
Cummins Engine Co. (Diesel Engine Company), and The Mead Corp. (Paper Products);
and Trustee of Vanderbilt University.
    
 
   
RAYMOND J. KLAPINSKY, (DOB: 12/7/1938) Secretary*
    
   
Managing Director of The Vanguard Group, Inc.; Secretary of The Vanguard Group,
Inc. and of each of the investment companies in The Vanguard Group.
    
 
   
THOMAS J. HIGGINS, (DOB: 5/21/1957) Treasurer*
    
   
Principal of The Vanguard Group, Inc.; Treasurer of each of the investment
companies in The Vanguard Group.
    
 
                                      B-13
<PAGE>   133
 
   
ROBERT D. SNOWDEN, (DOB: 9/4/1961) Controller*
    
   
Principal of The Vanguard Group, Inc.; Controller of each of the investment
companies in The Vanguard Group.
    
 
- ---------------
   
*Officers of the Trust are "interested persons" as defined in the Investment
Company Act of 1940.
    
 
THE VANGUARD GROUP
 
   
     Vanguard Index Trust is a member of The Vanguard Group of Investment
Companies, which consists of more than 30 investment companies. Through their
jointly-owned subsidiary, The Vanguard Group, Inc. ("Vanguard"), the Trust and
the other Trusts in The Vanguard Group obtain at cost virtually all of their
corporate management, administrative and distribution services. Vanguard also
provides investment advisory services on an at-cost basis to several of the
Vanguard Trusts.
    
 
   
     Vanguard employs a supporting staff of management and administrative
personnel needed to provide the requisite services to the Trusts and also
furnishes the Trusts with necessary office space, furnishings and equipment.
Each Trust pays its share of Vanguard's total expenses which are allocated among
the Trusts under methods approved by the Board of Trustees of each Trust. In
addition, each Trust bears its own direct expenses such as legal, auditing and
custodian fees.
    
 
   
     The Trust's Officers are Officers of Vanguard. No Officer or employee owns,
or is permitted to own, any securities of any external adviser for the Trusts.
    
 
   
     Vanguard adheres to a Code of Ethics established pursuant to Rule 17j-1
under the Investment Company Act of 1940. The Code is designed to prevent
unlawful practices in connection with the purchase or sale of securities by
persons associated with Vanguard. Under Vanguard's Code of Ethics certain
Officers and employees of Vanguard who are considered access persons are
permitted to engage in personal securities transactions. However, such
transactions are subject to procedures and guidelines similar to, and in many
cases more restrictive than, those recommended by a blue ribbon panel of mutual
fund industry executives.
    
 
   
     Vanguard was established and operates under an Amended and Restated Funds'
Service Agreement which was approved by the shareholders of each of the Trusts.
The Amended and Restated Funds' Service Agreement provides that each Vanguard
Trust may be called upon to invest up to .40% of its current net assets in
Vanguard as contributions to Vanguard's capitalization, and that there is no
limit on the dollar amount that each Vanguard Trust may contribute to Vanguard's
capitalization. The amounts which each of the Trusts has invested are adjusted
from time to time in order to maintain the proportionate relationship between
each Trust's relative net assets and its contribution to Vanguard's capital. At
December 31, 1998, each Fund had contributed capital to Vanguard representing
- --% of each Fund's net assets. The total amount contributed by the Trust was
$--, which represented --% of Vanguard's capitalization.
    
 
   
     MANAGEMENT.  Corporate management and administrative services include: (1)
executive staff; (2) accounting and financial; (3) legal and regulatory; (4)
shareholder account maintenance; (5) monitoring and control of custodian
relationships; (6) shareholder reporting; and (7) review and evaluation of
advisory and other services provided to the Trusts by third parties.
    
 
   
     DISTRIBUTION.  Vanguard Marketing Corporation, a wholly-owned subsidiary of
The Vanguard Group, Inc., provides all distribution and marketing activities for
the Trusts in the Group. The principal distribution expenses are for
advertising, promotional materials and marketing personnel. Distribution
services may also include organizing and offering to the public, from time to
time, one or more new investment companies which will become members of The
Vanguard Group. The Trustees and Officers of Vanguard determine the amount to be
spent annually on distribution activities, the manner and amount to be spent on
each Trust, and whether to organize new investment companies.
    
 
   
     One half of the distribution expenses of a marketing and promotional nature
is allocated among the various Vanguard Trusts based upon relative net assets.
The remaining one half of those expenses is allocated among the Trusts based
upon each Trust's sales for the preceding 24 months relative to the total sales
of the Trusts as a group, provided, however, that no Trust's aggregate quarterly
rate of contribution for distribution expenses of a marketing and promotional
nature shall exceed 125% of the average distribution expense rate for Vanguard,
and that no Trust shall incur annual distribution expenses in excess of 20/100
of 1% of its average month-end net assets. With respect to the Funds which have
two classes of shares, expenses paid to
    
 
                                      B-14
<PAGE>   134
 
   
The Vanguard Group that are associated with marketing and distribution
activities will be allocated to the class of shares of the Fund on behalf of
which the expenses were incurred by making such allocations to each share class
as if each such class were a separate Vanguard Trust. With respect to the Funds
which have two classes of shares, expenses associated with Vanguard's provision
of shareholder account services will be allocated to each share class on the
basis of the amount incurred by each share class.
    
 
   
     During the fiscal years ended December 31, 1996, 1997, and 1998, the Funds
incurred the following approximate amounts of The Vanguard Group's management
(including transfer agency), distribution, and marketing expenses:
    
 
   
<TABLE>
<CAPTION>
                            FUND                              1996    1997    1998
                            ----                              ----    ----    ----
<S>                                                           <C>     <C>     <C>
Vanguard Total Stock Market Index Fund......................   $--     $--     $--
Vanguard 500 Index Fund.....................................   $--     $--     $--
Vanguard Extended Market Index Fund.........................   $--     $--     $--
Vanguard Mid-Cap Index Fund.................................   $--     $--     $--
Vanguard Small-Cap Index Fund...............................   $--     $--     $--
Vanguard Value Index Fund...................................   $--     $--     $--
Vanguard Small-Cap Value Index Fund.........................   $--     $--     $--
Vanguard Growth Index Fund..................................   $--     $--     $--
Vanguard Small-Cap Growth Index Fund........................   $--     $--     $--
</TABLE>
    
 
   
     INVESTMENT ADVISORY SERVICES.  The Funds that comprise Vanguard Index Trust
receive all investment adviser services from Vanguard's Core Management Group.
These services are provided on an at-cost basis from money management staff
employed directly by Vanguard. The compensation and other expenses of this staff
are paid by the Vanguard Funds utilizing these services. During the fiscal years
ended December 31, 1996, 1997 and 1998, the Funds incurred expenses for
investment advisory services in the following amounts:
    
 
   
<TABLE>
<CAPTION>
                            FUND                               1996       1997      1998
                            ----                              -------    -------    ----
<S>                                                           <C>        <C>        <C>
Vanguard Total Stock Market Index Fund......................  $27,000    $56,000     $--
Vanguard 500 Index Fund.....................................  $20,000    $67,000     $--
Vanguard Extended Market Index Fund.........................  $27,000    $53,000     $--
Vanguard Mid-Cap Index Fund.................................      N/A        N/A     $--*
Vanguard Small-Cap Index Fund...............................  $29,000    $67,000     $--
Vanguard Value Index Fund...................................  $12,000    $22,000     $--
Vanguard Small-Cap Value Index Fund.........................      N/A        N/A     $--*
Vanguard Growth Index Fund..................................  $12,000    $22,000     $--
Vanguard Small-Cap Growth Index Fund........................      N/A        N/A     $--*
</TABLE>
    
 
- ---------------
   
* Since Inception, April 20, 1998.
    
 
   
TRUSTEE COMPENSATION
    
 
   
     The individuals in the following table serve as Trustees of all Vanguard
Trusts, and each Trust pays a proportionate share of the Trustees' compensation.
The Trusts employ their officers on a shared basis, as well. However, officers
are compensated by The Vanguard Group, Inc., not the Trusts.
    
 
   
INDEPENDENT TRUSTEES.  The Trusts compensate their independent Trustees -- that
is, the ones who are not also Officers of the Trust -- in three ways:
    
 
   
- -- The independent Trustees receive an annual fee for their service to the
   Trusts, which is subject to reduction based on absences from scheduled Board
   meetings.
    
 
   
- -- The independent Trustees are reimbursed for the travel and other expenses
   that they incur in attending Board meetings.
    
 
                                      B-15
<PAGE>   135
 
   
- -- Upon retirement, the independent Trustees receive an aggregate annual fee of
   $1,000 for each year served on the Board, up to fifteen years of service.
   This annual fee is paid for ten years following retirement, or until each
   Trustee's death.
    
 
   
"INTERESTED" TRUSTEES.  The Trusts' interested Trustees -- Messrs. Bogle and
Brennan -- receive no compensation for their service in that capacity. However,
they are paid in their role as Officers of The Vanguard Group, Inc.
    
 
   
COMPENSATION TABLE.  The following table provides compensation details for each
of the Trustees. For the Trust, we list the amounts paid as compensation and
accrued as retirement benefits by the Trust for each Trustee. In addition, the
table shows the total amount of benefits that we expect each Trustee to receive
from all Vanguard Trusts upon retirement, and the total amount of compensation
paid to each Trustee by all Vanguard Trusts. All information shown is for the
fiscal year ended December 31, 1998.
    
 
                              VANGUARD INDEX TRUST
                               COMPENSATION TABLE
 
   
<TABLE>
<CAPTION>
                                AGGREGATE     PENSION OR RETIREMENT       ESTIMATED        TOTAL COMPENSATION
                               COMPENSATION    BENEFITS ACCRUED AS     ANNUAL BENEFITS   FROM ALL VANGUARD FUNDS
      NAMES OF TRUSTEES         FROM TRUST    PART OF TRUST EXPENSES   UPON RETIREMENT     PAID TO TRUSTEES(1)
      -----------------        ------------   ----------------------   ---------------   -----------------------
<S>                            <C>            <C>                      <C>               <C>
John C. Bogle                    None              None                   None                None
John J. Brennan                  None              None                   None                None
Barbara Barnes Hauptfuhrer(2)     $--              $--                     $--                 $--
JoAnn Heffernan Heisen            $--              $--                     $--                 $--
Robert E. Cawthorn(2)             $--              $--                     $--                 $--
Bruce K. MacLaury                 $--              $--                     $--                 $--
Burton G. Malkiel                 $--              $--                     $--                 $--
Alfred M. Rankin, Jr.             $--              $--                     $--                 $--
John C. Sawhill                   $--              $--                     $--                 $--
James O. Welch, Jr.               $--              $--                     $--                 $--
J. Lawrence Wilson                $--              $--                     $--                 $--
</TABLE>
    
 
   
(1) The amounts reported in this column reflect the total compensation paid to
    each Trustee for their service as Director or Trustee of 36 Vanguard Funds
    (35 in the case of Mr. Malkiel; 28 in the case of Mr. MacLaury).
    
   
(2) Mr. Cawthorn and Mrs. Hauptfuhrer have retired from the Trust's Board,
    effective May 31, 1998 and December 31, 1998, respectively.
    
 
                                      B-16
<PAGE>   136
 
                             PORTFOLIO TRANSACTIONS
 
   
     In placing portfolio transactions on behalf of a Fund, Vanguard's Core
Management Group uses its best judgment to choose the broker most capable of
providing the brokerage services necessary to obtain best available price and
most favorable execution. The full range and quality of brokerage services
available are considered in making these determinations. In those instances
where it is reasonably determined that more than one broker can offer the
brokerage services needed to obtain the best available price and most favorable
execution, consideration will be given to those brokers which supply statistical
information and provide other services in addition to execution services to the
Trust.
    
 
   
     Since the Funds do not market their shares through intermediary brokers or
dealers, it is not the Funds' practice to allocate brokerage or principal
business on the basis of sales of their shares which may be made through such
firms. However, a Fund may place portfolio orders with qualified broker-dealers
who recommend the Fund to clients, and may, when a number of brokers and dealers
can provide best price and execution on a particular transaction, consider the
sale of Fund shares by a broker or dealer in selecting among broker dealers.
    
 
   
     During the fiscal years ended December 31, 1996, 1997 and 1998, the Funds
paid brokerage commissions in the following amounts:
    
 
   
<TABLE>
<CAPTION>
                                                                1996    1997    1998
                                                                ----    ----    ----
<S>                                                             <C>     <C>     <C>
Vanguard Total Stock Market Index Fund                           $--     $--     $--
Vanguard 500 Index Fund                                          $--     $--     $--
Vanguard Extended Market Index Fund                              $--     $--     $--
Vanguard Mid-Cap Index Fund                                      $--     $--     $--
Vanguard Small-Cap Index Fund                                    $--     $--     $--
Vanguard Value Index Fund                                        $--     $--     $--
Vanguard Small-Cap Value Index Fund                              $--     $--     $--
Vanguard Growth Index Fund                                       $--     $--     $--
Vanguard Small-Cap Growth Index Fund                             $--     $--     $--
</TABLE>
    
 
                                      B-17
<PAGE>   137
 
                              PERFORMANCE MEASURES
 
   
     Vanguard may use reprinted material discussing The Vanguard Group, Inc. or
any of the member trusts of The Vanguard Group of Investment Companies.
    
 
     Each of the investment company members of The Vanguard Group, including
Vanguard Index Trust, may from time to time, use one or more of the following
unmanaged indexes for comparative performance purposes.
 
   
STANDARD & POOR'S 500 COMPOSITE STOCK PRICE INDEX -- includes stocks selected by
Standard & Poor's Index Committee to include leading companies in leading
industries and to reflect the U.S. stock market.
    
 
   
STANDARD & POOR'S 500/BARRA VALUE INDEX -- consists of the stocks in the
Standard & Poor's 500 Composite Stock Price Index ("S&P 500") with the lowest
price-to-book ratios, comprising 50% of the market capitalization of the S&P
500.
    
 
STANDARD & POOR'S MIDCAP 400 INDEX -- is composed of 400 medium sized domestic
stocks.
 
STANDARD & POOR'S SMALLCAP 600/BARRA VALUE INDEX -- contains stocks of the S&P
SmallCap 600 Index which have a lower than average price-to-book ratio.
 
STANDARD & POOR'S SMALLCAP 600/BARRA GROWTH INDEX -- contains stocks of the S&P
SmallCap 600 Index which have a higher than average price-to-book ratio.
 
RUSSELL 1000 VALUE INDEX -- consists of the stocks in the Russell 1000 Index
(comprising the 1,000 largest U.S.-based companies measured by total market
capitalization) with the lowest price-to-book ratios, comprising 50% of the
market capitalization of the Russell 1000.
 
WILSHIRE 5000 EQUITY INDEX -- consists of more than 7,000 common equity
securities, covering all stocks in the U.S. for which daily pricing is
available.
 
WILSHIRE 4500 EQUITY INDEX -- consists of all stocks in the Wilshire 5000 except
for the 500 stocks in the Standard & Poor's 500 Index.
 
BOND BUYER MUNICIPAL BOND INDEX -- is a yield index on current coupon high-grade
general obligation municipal bonds.
 
RUSSELL 2000 STOCK INDEX -- is composed of approximately 2,000 small
capitalization stocks.
 
MERRILL LYNCH CORPORATE & GOVERNMENT BOND INDEX -- consists of over 4,500 U.S.
Treasury, Agency and investment grade corporate bonds.
 
MORGAN STANLEY CAPITAL INTERNATIONAL EAFE INDEX -- is an arithmetic, market
value-weighted average of the performance of over 900 securities listed on the
stock exchanges of countries in Europe, Australasia and the Far East.
 
GOLDMAN SACHS 100 CONVERTIBLE BOND INDEX -- currently includes 71 bonds and 29
preferred stocks. The original list of names was generated by screening for
convertible issues of $100 million or greater in market capitalization. The
index is priced monthly.
 
SALOMON BROTHERS GNMA INDEX -- includes pools of mortgages originated by private
lenders and guaranteed by the mortgage pools of the Government National Mortgage
Association.
 
SALOMON BROTHERS HIGH-GRADE CORPORATE BOND INDEX -- consists of publicly issued,
non-convertible corporate bonds rated Aa or Aaa. It is a value-weighted, total
return index, including approximately 800 issues with maturities of 12 years or
greater.
 
SALOMON BROTHERS BROAD INVESTMENT-GRADE BOND INDEX -- is a market-weighted index
that contains approximately 4700 individually priced investment-grade corporate
bonds rated BBB or better, U.S. Treasury/agency issues and mortgage pass-through
securities.
 
LEHMAN LONG-TERM TREASURY BOND INDEX -- is composed of all bonds covered by the
Shearson Lehman Hutton Treasury Bond Index with maturities of 10 years or
greater.
 
NASDAQ INDUSTRIAL INDEX -- is composed of more than 3,000 industrial issues. It
is a value-weighted index calculated on price change only and does not include
income.
 
COMPOSITE INDEX -- 70% Standard & Poor's 500 Index and 30% NASDAQ Industrial
Index.
 
                                      B-18
<PAGE>   138
 
COMPOSITE INDEX -- 65% Standard & Poor's 500 Index and 35% Lehman Long-Term
Corporate AA or Better Bond Index.
 
COMPOSITE INDEX -- 65% Lehman Long-Term Corporate AA or Better Bond Index and a
35% weighting in a blended equity composite (75% Standard & Poor's/BARRA Value
Index, 12.5% Standard & Poor's Utilities Index and 12.5% Standard & Poor's
Telephone Index).
 
LEHMAN LONG-TERM CORPORATE AA OR BETTER BOND INDEX -- consists of all publicly
issued, fixed rate, nonconvertible investment grade, dollar-denominated,
SEC-registered corporate debt rated AA or AAA.
 
LEHMAN BROTHERS AGGREGATE BOND INDEX -- is a market-weighted index that contains
individually priced U.S. Treasury, agency, corporate, and mortgage pass-through
securities corporate rated Baa- or better. The Index has a market value of over
$4 trillion.
 
LEHMAN BROTHERS MUTUAL FUND SHORT (1-5) GOVERNMENT/CORPORATE INDEX -- is a
market-weighted index that contains individually priced U.S. Treasury, agency,
and corporate investment grade bonds rated BBB- or better with maturities
between 1 and 5 years. The index has a market value of over $1.6 trillion.
 
LEHMAN BROTHERS MUTUAL FUND INTERMEDIATE (5-10) GOVERNMENT/CORPORATE INDEX -- is
a market-weighted index that contains individually priced U.S. Treasury, agency,
and corporate securities rated BBB- or better with maturities between 5 and 10
years. The index has a market value of over $700 billion.
 
LEHMAN BROTHERS LONG (10+) GOVERNMENT/CORPORATE INDEX -- is a market-weighted
index that contains individually priced U.S. Treasury, agency, and corporate
securities rated BBB- or better with maturities greater than 10 years. The index
has a market value of over $900 billion.
 
LEHMAN CORPORATE (Baa) BOND INDEX -- all publicly offered fixed-rate,
nonconvertible domestic corporate bonds rated Baa by Moody's, with a maturity
longer than 1 year and with more than $25 million outstanding. This index
includes over 1,000 issues.
 
LEHMAN BROTHERS LONG-TERM CORPORATE BOND INDEX -- is a subset of the Lehman
Corporate Bond Index covering all corporate, publicly issued, fixed-rate
nonconvertible U.S. debt issues rated at least Baa, with at least $50 million
principal outstanding and maturity greater than 10 years.
 
                              FINANCIAL STATEMENTS
 
   
     The Trust's Financial Statements as of and for the year ended December 31,
1998, appearing in the Vanguard Index Trust 1998 Annual Report to Shareholders
and inserts thereto, and the reports thereon of PricewaterhouseCoopers LLP,
independent accountants, also appearing therein, are incorporated by reference
in this Statement of Additional Information. For a more complete discussion of
the performance, please see the Trust's Annual Report to Shareholders, which may
be obtained without charge.
    
 
                                      B-19
<PAGE>   139
 
                                     PART C
                              VANGUARD INDEX TRUST
                               OTHER INFORMATION
 
   
ITEM 23. EXHIBITS
    
 
   
<TABLE>
<S>  <C>
(a)  Declaration of Trust*
(b)  By-Laws*
(c)  Reference is made to Articles III and V of the Registrant's
     Declaration of Trust
(d)  Not Applicable
(e)  Not Applicable
(f)  Reference is made to the section entitled "Management of the
     Trust" in the Registrant's Statement of Additional
     Information
(g)  Custodian Agreements*
(h)  Amended and Restated Funds' Service Agreement*
(i)  Legal Opinion*
(j)  Consent of Independent Accountants**
(k)  Not Applicable.
(l)  Not Applicable.
(m)  Not Applicable.
(n)  Financial Data Schedules+
(o)  Rule 18f-3 Plan*
</TABLE>
    
 
- ---------------
   
 * Filed Previously
    
   
 ** To Be Filed By Amendment
    
   
 + Filed Herewith
    
 
   
ITEM 24. PERSONS CONTROLLED BY OR UNDER COMMON CONTROL WITH REGISTRANT
    
 
   
     Registrant is not controlled by or under common control with any person.
    
 
   
ITEM 25. INDEMNIFICATION
    
 
   
     The Registrant's organizational documents contain provisions indemnifying
Trustees and Officers against liability incurred in their official capacity.
Article VII, Section 2 of the Declaration of Trust provides that the Registrant
may indemnify and hold harmless each and every Trustee and Officer from and
against any and all claims, demands, costs, losses, expenses, and damages
whatsoever arising out of or related to the performance of his or her duties as
a Trustee or Officer. However, this provision does not cover any liability to
which a Trustee or Officer would otherwise be subject by reason of willful
misfeasance, bad faith, gross negligence or reckless disregard of the duties
involved in the conduct of his or her office. Article VI of the By-Laws
generally provides that the Registrant shall indemnify its Trustees and Officers
from any liability arising out of their past or present service in that
capacity. Among other things, this provision excludes any liability arising by
reason of willful misfeasance, bad faith, gross negligence, or the reckless
disregard of the duties involved in the conduct of the Trustee's or Officer's
office with the Registrant.
    
 
   
ITEM 26. BUSINESS AND OTHER CONNECTIONS OF THE INVESTMENT ADVISER
    
 
   
     Investment advisory services are provided to the Registrant on an at-cost
basis by The Vanguard Group, Inc., a jointly-owned subsidiary of the Registrant
and the other Trusts in the Vanguard Group of Investment Companies. See the
information concerning The Vanguard Group, Inc. set forth in Parts A and B. For
information as to any other business, vocation or employment of a substantial
nature in which each director or officer of the Registrant's investment advisor
is or has been engaged for his own account or in the capacity of trustee,
officer, employee, partner or trustee, reference is made to Form ADV (File
#801-11953) filed by it under the Investment Advisers Act of 1940.
    
<PAGE>   140
 
   
ITEM 27. PRINCIPAL UNDERWRITERS
    
 
   
(a) Not Applicable
    
 
   
(b) Not Applicable
    
 
   
(c) Not Applicable
    
 
   
ITEM 28. LOCATION OF ACCOUNTS AND RECORDS
    
 
   
     The books, accounts and other documents required by Section 31(a) under the
Investment Company Act and the rules promulgated thereunder will be maintained
in the physical possession of Registrant; Registrant's Transfer Agent, The
Vanguard Group, Inc., Valley Forge, Pennsylvania 19482; and the Registrant's
Custodians, State Street Bank and Trust Company, 225 Franklin Street, Boston, MA
02105, and First Union National Bank, PA4943, 530 Walnut Street, Philadelphia,
PA 19106.
    
 
   
ITEM 29. MANAGEMENT SERVICES
    
 
   
     Other than as set forth under the description of The Vanguard Group in Part
B of this Registration Statement, Registrant is not a party to any
management-related service contract.
    
 
   
ITEM 30. UNDERTAKINGS
    
 
   
     Not applicable
    
<PAGE>   141
 
                                   SIGNATURES
 
   
     Pursuant to the requirements of the Securities Act of 1933 and the
Investment Company Act of 1940, the Registrant hereby certifies that it has duly
caused this Post-Effective Amendment to this Registration Statement to be signed
on its behalf by the undersigned, thereunto duly authorized, in the Town of
Valley Forge and the Commonwealth of Pennsylvania, on the 25th day of February,
1999.
    
 
VANGUARD INDEX TRUST
 
By:
- ---------------------------------------
        John J. Brennan, Chairman &
          Chief Executive Officer
 
     Pursuant to the requirements of the Securities Act of 1933, this
Post-Effective Amendment to the Registration Statement has been signed below by
the following persons in the capacities and on the date indicated:
 
   
BY: (Heidi Stam)*
    
    John C. Bogle, Senior Chairman of the Board and Trustee
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
    John J. Brennan, Chairman, Trustee and Chief Executive Officer
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
   
    JoAnn Heffernan Heisen, Trustee
    
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
    Bruce K. MacLaury, Trustee
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
    Burton G. Malkiel, Trustee
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
    Alfred M. Rankin, Jr., Trustee
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
    John C. Sawhill, Trustee
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
    James O. Welch, Jr., Trustee
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
    J. Lawrence Wilson, Trustee
   
    February 25, 1999
    
 
   
BY: (Heidi Stam)*
    
   
    Thomas J. Higgins, Treasurer and Principal
    
    Financial Officer and Accounting Officer
   
    February 25, 1999
    
 
   
* By Power-of-Attorney. See File Number 33-4424, filed on January 25, 1999.
  Incorporated by reference.
    
<PAGE>   142
 
                               INDEX TO EXHIBITS
 
   
<TABLE>
<S>                                                           <C>
Financial Data Schedules....................................   Ex-99.BN
</TABLE>
    

<PAGE>   1
[ARTICLE] 6
[RESTATED] 
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 01
   [NAME] VANGUARD 500 INDEX FUND
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                       43,332,020
[INVESTMENTS-AT-VALUE]                      74,321,906
[RECEIVABLES]                                  824,609
[ASSETS-OTHER]                                  12,489
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                              75,159,004
[PAYABLE-FOR-SECURITIES]                       697,610
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                      232,868
[TOTAL-LIABILITIES]                            930,478
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                    42,935,110
[SHARES-COMMON-STOCK]                          651,398
[SHARES-COMMON-PRIOR]                          547,990
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                           6,151
[ACCUMULATED-NET-GAINS]                        296,685
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                    31,002,882
[NET-ASSETS]                                74,228,526
[DIVIDEND-INCOME]                              898,388
[INTEREST-INCOME]                               32,484
[OTHER-INCOME]                                     995
[EXPENSES-NET]                                 110,303
[NET-INVESTMENT-INCOME]                        821,564
[REALIZED-GAINS-CURRENT]                     1,519,211
[APPREC-INCREASE-CURRENT]                   13,039,461
[NET-CHANGE-FROM-OPS]                       15,380,236
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                      822,586
[DISTRIBUTIONS-OF-GAINS]                       262,081
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                        205,796
[NUMBER-OF-SHARES-REDEEMED]                    111,820
[SHARES-REINVESTED]                              9,433
[NET-CHANGE-IN-ASSETS]                      24,870,903
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                       44,740
[OVERDISTRIB-NII-PRIOR]                          5,129
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               80
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                110,303
[AVERAGE-NET-ASSETS]                        60,729,871
[PER-SHARE-NAV-BEGIN]                            90.07
[PER-SHARE-NII]                                   1.33
[PER-SHARE-GAIN-APPREC]                          24.30
[PER-SHARE-DIVIDEND]                              1.33
[PER-SHARE-DISTRIBUTIONS]                         0.42
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                             113.95
[EXPENSE-RATIO]                                   0.18
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 021
   [NAME] VANGUARD EXTENDED MARKET INDEX FUND-INVESTOR SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        2,891,395
[INVESTMENTS-AT-VALUE]                       3,649,262
[RECEIVABLES]                                  162,137
[ASSETS-OTHER]                                     574
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                               3,811,973
[PAYABLE-FOR-SECURITIES]                        83,155
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                      333,659
[TOTAL-LIABILITIES]                            416,814
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     2,458,296
[SHARES-COMMON-STOCK]                           95,929
[SHARES-COMMON-PRIOR]                           88,529
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                             133
[ACCUMULATED-NET-GAINS]                        176,135
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                       760,861
[NET-ASSETS]                                 2,938,675
[DIVIDEND-INCOME]                               37,381
[INTEREST-INCOME]                                4,750
[OTHER-INCOME]                                   4,539
[EXPENSES-NET]                                   6,863
[NET-INVESTMENT-INCOME]                         39,807
[REALIZED-GAINS-CURRENT]                       367,082
[APPREC-INCREASE-CURRENT]                    (154,493)
[NET-CHANGE-FROM-OPS]                          252,396
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                       33,806
[DISTRIBUTIONS-OF-GAINS]                       195,606
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                         21,213
[NUMBER-OF-SHARES-REDEEMED]                     21,009
[SHARES-REINVESTED]                              7,196
[NET-CHANGE-IN-ASSETS]                         257,680
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                       34,973
[OVERDISTRIB-NII-PRIOR]                            578
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               73
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                  6,897
[AVERAGE-NET-ASSETS]                         2,782,988
[PER-SHARE-NAV-BEGIN]                            30.76
[PER-SHARE-NII]                                  0.388
[PER-SHARE-GAIN-APPREC]                          2.025
[PER-SHARE-DIVIDEND]                             0.373
[PER-SHARE-DISTRIBUTIONS]                        2.170
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              30.63
[EXPENSE-RATIO]                                   0.23
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 022
   [NAME] VANGUARD EXTENDED MARKET INDEX FUND-INSTITUTIONAL SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        2,891,395
[INVESTMENTS-AT-VALUE]                       3,649,262
[RECEIVABLES]                                  162,137
[ASSETS-OTHER]                                     574
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                               3,811,973
[PAYABLE-FOR-SECURITIES]                        83,155
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                      333,659
[TOTAL-LIABILITIES]                            416,814
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     2,458,296
[SHARES-COMMON-STOCK]                           14,901
[SHARES-COMMON-PRIOR]                           13,482
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                             133
[ACCUMULATED-NET-GAINS]                        176,135
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                       760,861
[NET-ASSETS]                                   456,484
[DIVIDEND-INCOME]                               37,381
[INTEREST-INCOME]                                4,750
[OTHER-INCOME]                                   4,539
[EXPENSES-NET]                                   6,863
[NET-INVESTMENT-INCOME]                         39,807
[REALIZED-GAINS-CURRENT]                       367,082
[APPREC-INCREASE-CURRENT]                    (154,493)
[NET-CHANGE-FROM-OPS]                          252,396
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                        5,556
[DISTRIBUTIONS-OF-GAINS]                        30,314
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                          7,627
[NUMBER-OF-SHARES-REDEEMED]                      7,244
[SHARES-REINVESTED]                              1,037
[NET-CHANGE-IN-ASSETS]                         257,680
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                       34,973
[OVERDISTRIB-NII-PRIOR]                            578
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               73
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                  6,897
[AVERAGE-NET-ASSETS]                           455,192
[PER-SHARE-NAV-BEGIN]                            30.76
[PER-SHARE-NII]                                  0.427
[PER-SHARE-GAIN-APPREC]                          2.025
[PER-SHARE-DIVIDEND]                             0.412
[PER-SHARE-DISTRIBUTIONS]                        2.170
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              30.63
[EXPENSE-RATIO]                                   0.10
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[RESTATED] 
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 031
   [NAME] VANGUARD TOTAL STOCK MARKET INDEX FUND-INVESTOR SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        8,365,070
[INVESTMENTS-AT-VALUE]                      11,954,647
[RECEIVABLES]                                   85,915
[ASSETS-OTHER]                                   1,925
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                              12,042,487
[PAYABLE-FOR-SECURITIES]                         1,572
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                      287,796
[TOTAL-LIABILITIES]                            289,368
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     8,092,915
[SHARES-COMMON-STOCK]                          339,456
[SHARES-COMMON-PRIOR]                          224,899
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                             242
[ACCUMULATED-NET-GAINS]                         41,321
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                     3,619,125
[NET-ASSETS]                                 9,307,762
[DIVIDEND-INCOME]                              118,554
[INTEREST-INCOME]                               23,390
[OTHER-INCOME]                                   3,182
[EXPENSES-NET]                                  15,820
[NET-INVESTMENT-INCOME]                        129,306
[REALIZED-GAINS-CURRENT]                        77,195
[APPREC-INCREASE-CURRENT]                    1,758,376
[NET-CHANGE-FROM-OPS]                        1,964,877
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                      100,035
[DISTRIBUTIONS-OF-GAINS]                        38,015
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                        160,242
[NUMBER-OF-SHARES-REDEEMED]                     50,676
[SHARES-REINVESTED]                              4,991
[NET-CHANGE-IN-ASSETS]                       5,156,662
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                       12,235
[OVERDISTRIB-NII-PRIOR]                            956
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               82
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                 15,857
[AVERAGE-NET-ASSETS]                         6,942,466
[PER-SHARE-NAV-BEGIN]                            22.64
[PER-SHARE-NII]                                  0.336
[PER-SHARE-GAIN-APPREC]                          4.898
[PER-SHARE-DIVIDEND]                             0.329
[PER-SHARE-DISTRIBUTIONS]                        0.125
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              27.42
[EXPENSE-RATIO]                                   0.20
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[RESTATED] 
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 032
   [NAME] VANGUARD TOTAL STOCK MARKET INDEX FUND-INSTITUTIONAL SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        8,365,070
[INVESTMENTS-AT-VALUE]                      11,954,647
[RECEIVABLES]                                   85,915
[ASSETS-OTHER]                                   1,925
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                              12,042,487
[PAYABLE-FOR-SECURITIES]                         1,572
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                      287,796
[TOTAL-LIABILITIES]                            289,368
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     8,092,915
[SHARES-COMMON-STOCK]                           89,179
[SHARES-COMMON-PRIOR]                           66,413
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                             242
[ACCUMULATED-NET-GAINS]                         41,321
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                     3,619,125
[NET-ASSETS]                                 2,445,357
[DIVIDEND-INCOME]                              118,554
[INTEREST-INCOME]                               23,390
[OTHER-INCOME]                                   3,182
[EXPENSES-NET]                                  15,820
[NET-INVESTMENT-INCOME]                        129,306
[REALIZED-GAINS-CURRENT]                        77,195
[APPREC-INCREASE-CURRENT]                    1,758,376
[NET-CHANGE-FROM-OPS]                        1,964,877
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                       28,557
[DISTRIBUTIONS-OF-GAINS]                        10,094
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                         33,554
[NUMBER-OF-SHARES-REDEEMED]                     12,173
[SHARES-REINVESTED]                              1,385
[NET-CHANGE-IN-ASSETS]                       5,156,662
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                       12,235
[OVERDISTRIB-NII-PRIOR]                            956
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               82
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                 15,857
[AVERAGE-NET-ASSETS]                         1,907,075
[PER-SHARE-NAV-BEGIN]                            22.64
[PER-SHARE-NII]                                  0.359
[PER-SHARE-GAIN-APPREC]                          4.898
[PER-SHARE-DIVIDEND]                             0.352
[PER-SHARE-DISTRIBUTIONS]                        0.125
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              27.42
[EXPENSE-RATIO]                                   0.10
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[RESTATED] 
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 041
   [NAME] VANGUARD VALUE INDEX FUND-INVESTOR SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        2,077,416
[INVESTMENTS-AT-VALUE]                       2,622,203
[RECEIVABLES]                                  355,862
[ASSETS-OTHER]                                     442
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                               2,978,507
[PAYABLE-FOR-SECURITIES]                       359,770
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                       12,024
[TOTAL-LIABILITIES]                            371,794
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     1,982,252
[SHARES-COMMON-STOCK]                          107,548
[SHARES-COMMON-PRIOR]                           86,130
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                             551
[ACCUMULATED-NET-GAINS]                         80,108
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                       544,904
[NET-ASSETS]                                 2,420,609
[DIVIDEND-INCOME]                               41,768
[INTEREST-INCOME]                                  398
[OTHER-INCOME]                                      54
[EXPENSES-NET]                                   4,763
[NET-INVESTMENT-INCOME]                         37,457
[REALIZED-GAINS-CURRENT]                       148,039
[APPREC-INCREASE-CURRENT]                      110,054
[NET-CHANGE-FROM-OPS]                          295,550
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                       36,542
[DISTRIBUTIONS-OF-GAINS]                        98,153
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                         39,652
[NUMBER-OF-SHARES-REDEEMED]                     23,806
[SHARES-REINVESTED]                              5,572
[NET-CHANGE-IN-ASSETS]                         811,172
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                       34,787
[OVERDISTRIB-NII-PRIOR]                            186
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               37
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                  4,763
[AVERAGE-NET-ASSETS]                         2,149,394
[PER-SHARE-NAV-BEGIN]                            20.85
[PER-SHARE-NII]                                  0.366
[PER-SHARE-GAIN-APPREC]                          2.647
[PER-SHARE-DIVIDEND]                             0.363
[PER-SHARE-DISTRIBUTIONS]                        0.990
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              22.51
[EXPENSE-RATIO]                                   0.22
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[RESTATED] 
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 042
   [NAME] VANGUARD VALUE INDEX FUND-INSTITUTIONAL SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   OTHER
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JUL-02-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        2,077,416
[INVESTMENTS-AT-VALUE]                       2,622,203
[RECEIVABLES]                                  355,862
[ASSETS-OTHER]                                     442
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                               2,978,507
[PAYABLE-FOR-SECURITIES]                       359,770
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                       12,024
[TOTAL-LIABILITIES]                            371,794
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     1,982,252
[SHARES-COMMON-STOCK]                            8,269
[SHARES-COMMON-PRIOR]                                0
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                             551
[ACCUMULATED-NET-GAINS]                         80,108
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                       544,904
[NET-ASSETS]                                   186,104
[DIVIDEND-INCOME]                               41,768
[INTEREST-INCOME]                                  398
[OTHER-INCOME]                                      54
[EXPENSES-NET]                                   4,763
[NET-INVESTMENT-INCOME]                         37,457
[REALIZED-GAINS-CURRENT]                       148,039
[APPREC-INCREASE-CURRENT]                      110,054
[NET-CHANGE-FROM-OPS]                          295,550
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                        1,280
[DISTRIBUTIONS-OF-GAINS]                         4,565
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                          8,040
[NUMBER-OF-SHARES-REDEEMED]                          3
[SHARES-REINVESTED]                                232
[NET-CHANGE-IN-ASSETS]                         811,172
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                       34,787
[OVERDISTRIB-NII-PRIOR]                            186
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               37
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                  4,763
[AVERAGE-NET-ASSETS]                            60,885
[PER-SHARE-NAV-BEGIN]                            23.22
[PER-SHARE-NII]                                  0.196
[PER-SHARE-GAIN-APPREC]                         (0.06)
[PER-SHARE-DIVIDEND]                             0.236
[PER-SHARE-DISTRIBUTIONS]                         0.61
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              22.51
[EXPENSE-RATIO]                                   0.12
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[RESTATED] 
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 051
   [NAME] VANGUARD GROWTH INDEX FUND-INVESTOR SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        4,947,187
[INVESTMENTS-AT-VALUE]                       6,898,318
[RECEIVABLES]                                  835,822
[ASSETS-OTHER]                                   1,058
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                               7,735,198
[PAYABLE-FOR-SECURITIES]                       856,779
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                        9,919
[TOTAL-LIABILITIES]                            866,698
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     4,877,998
[SHARES-COMMON-STOCK]                          209,802
[SHARES-COMMON-PRIOR]                          104,984
[ACCUMULATED-NII-CURRENT]                          374
[OVERDISTRIBUTION-NII]                               0
[ACCUMULATED-NET-GAINS]                         38,663
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                     1,951,465
[NET-ASSETS]                                 6,644,305
[DIVIDEND-INCOME]                               45,207
[INTEREST-INCOME]                                1,732
[OTHER-INCOME]                                      14
[EXPENSES-NET]                                   8,993
[NET-INVESTMENT-INCOME]                         37,960
[REALIZED-GAINS-CURRENT]                        72,886
[APPREC-INCREASE-CURRENT]                    1,404,145
[NET-CHANGE-FROM-OPS]                        1,514,991
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                       36,372
[DISTRIBUTIONS-OF-GAINS]                        23,155
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                        140,735
[NUMBER-OF-SHARES-REDEEMED]                     37,803
[SHARES-REINVESTED]                              1,885
[NET-CHANGE-IN-ASSETS]                       4,503,167
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                            0
[OVERDISTRIB-NII-PRIOR]                            521
[OVERDIST-NET-GAINS-PRIOR]                       8,937
[GROSS-ADVISORY-FEES]                               37
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                  8,993
[AVERAGE-NET-ASSETS]                         4,065,327
[PER-SHARE-NAV-BEGIN]                            22.53
[PER-SHARE-NII]                                  0.230
[PER-SHARE-GAIN-APPREC]                          9.244
[PER-SHARE-DIVIDEND]                             0.219
[PER-SHARE-DISTRIBUTIONS]                        0.115
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              31.67
[EXPENSE-RATIO]                                   0.22
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[RESTATED] 
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 052
   [NAME] VANGUARD GROWTH INDEX FUND-INSTITUTIONAL SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   OTHER
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             MAY-14-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        4,947,187
[INVESTMENTS-AT-VALUE]                       6,898,318
[RECEIVABLES]                                  835,822
[ASSETS-OTHER]                                   1,058
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                               7,735,198
[PAYABLE-FOR-SECURITIES]                       856,779
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                        9,919
[TOTAL-LIABILITIES]                            866,698
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     4,877,998
[SHARES-COMMON-STOCK]                            7,079
[SHARES-COMMON-PRIOR]                                0
[ACCUMULATED-NII-CURRENT]                          374
[OVERDISTRIBUTION-NII]                               0
[ACCUMULATED-NET-GAINS]                         38,663
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                     1,951,465
[NET-ASSETS]                                   224,195
[DIVIDEND-INCOME]                               45,207
[INTEREST-INCOME]                                1,732
[OTHER-INCOME]                                      14
[EXPENSES-NET]                                   8,993
[NET-INVESTMENT-INCOME]                         37,960
[REALIZED-GAINS-CURRENT]                        72,886
[APPREC-INCREASE-CURRENT]                    1,404,145
[NET-CHANGE-FROM-OPS]                        1,514,991
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                          693
[DISTRIBUTIONS-OF-GAINS]                           813
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                          7,955
[NUMBER-OF-SHARES-REDEEMED]                        925
[SHARES-REINVESTED]                                 49
[NET-CHANGE-IN-ASSETS]                       4,503,167
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                            0
[OVERDISTRIB-NII-PRIOR]                            521
[OVERDIST-NET-GAINS-PRIOR]                       8,937
[GROSS-ADVISORY-FEES]                               37
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                  8,993
[AVERAGE-NET-ASSETS]                            94,331
[PER-SHARE-NAV-BEGIN]                            26.49
[PER-SHARE-NII]                                  0.167
[PER-SHARE-GAIN-APPREC]                          5.315
[PER-SHARE-DIVIDEND]                             0.187
[PER-SHARE-DISTRIBUTIONS]                        0.115
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              31.67
[EXPENSE-RATIO]                                   0.12
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[RESTATED] 
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 061
   [NAME] VANGUARD SMALL-CAP INDEX FUND-INVESTOR SHARES
[MULTIPLIER] 1,000
[CURRENCY] U.S. DOLLARS
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                        2,986,293
[INVESTMENTS-AT-VALUE]                       3,228,056
[RECEIVABLES]                                   33,117
[ASSETS-OTHER]                                     558
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                               3,261,731
[PAYABLE-FOR-SECURITIES]                        20,743
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                      208,632
[TOTAL-LIABILITIES]                            229,375
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                     2,769,161
[SHARES-COMMON-STOCK]                          130,588
[SHARES-COMMON-PRIOR]                          111,668
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                             641
[ACCUMULATED-NET-GAINS]                         14,857
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                       248,979
[NET-ASSETS]                                 2,768,079
[DIVIDEND-INCOME]                               38,503
[INTEREST-INCOME]                                5,515
[OTHER-INCOME]                                   2,866
[EXPENSES-NET]                                   6,682
[NET-INVESTMENT-INCOME]                         40,202
[REALIZED-GAINS-CURRENT]                       199,544
[APPREC-INCREASE-CURRENT]                    (318,857)
[NET-CHANGE-FROM-OPS]                         (79,111)
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                       37,309
[DISTRIBUTIONS-OF-GAINS]                       188,747
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                         42,704
[NUMBER-OF-SHARES-REDEEMED]                     33,911
[SHARES-REINVESTED]                             10,127
[NET-CHANGE-IN-ASSETS]                         243,062
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                       18,730
[OVERDISTRIB-NII-PRIOR]                            381
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                              100
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                  6,686
[AVERAGE-NET-ASSETS]                         2,686,647
[PER-SHARE-NAV-BEGIN]                            23.75
[PER-SHARE-NII]                                  0.311
[PER-SHARE-GAIN-APPREC]                        (1.007)
[PER-SHARE-DIVIDEND]                             0.304
[PER-SHARE-DISTRIBUTIONS]                        1.550
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              21.20
[EXPENSE-RATIO]                                   0.24
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 062
   [NAME] VANGUARD SMALL-CAP INDEX FUND-INSTITUTIONAL SHARES
[MULTIPLIER] 1000
[CURRENCY] US
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   YEAR
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             JAN-01-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                          2986293
[INVESTMENTS-AT-VALUE]                         3228056
[RECEIVABLES]                                    33117
[ASSETS-OTHER]                                     558
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                                 3261731
[PAYABLE-FOR-SECURITIES]                         20743
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                       208632
[TOTAL-LIABILITIES]                             229375
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                       2769161
[SHARES-COMMON-STOCK]                            12467
[SHARES-COMMON-PRIOR]                             5762
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                             641
[ACCUMULATED-NET-GAINS]                          14857
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                        248979
[NET-ASSETS]                                    264277
[DIVIDEND-INCOME]                                38503
[INTEREST-INCOME]                                 5515
[OTHER-INCOME]                                    2866
[EXPENSES-NET]                                    6682
[NET-INVESTMENT-INCOME]                          40202
[REALIZED-GAINS-CURRENT]                        199544
[APPREC-INCREASE-CURRENT]                     (318857)
[NET-CHANGE-FROM-OPS]                          (79111)
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                         3153
[DISTRIBUTIONS-OF-GAINS]                         14670
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                           6477
[NUMBER-OF-SHARES-REDEEMED]                        385
[SHARES-REINVESTED]                                613
[NET-CHANGE-IN-ASSETS]                          243062
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                        18730
[OVERDISTRIB-NII-PRIOR]                            381
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                              100
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                   6686
[AVERAGE-NET-ASSETS]                            197759
[PER-SHARE-NAV-BEGIN]                            23.75
[PER-SHARE-NII]                                  0.336
[PER-SHARE-GAIN-APPREC]                        (1.007)
[PER-SHARE-DIVIDEND]                             0.329
[PER-SHARE-DISTRIBUTIONS]                        1.550
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              21.20
[EXPENSE-RATIO]                                   0.12
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 071
   [NAME] VANGUARD MID-CAP INDEX FUND-INVESTOR SHARES
[MULTIPLIER] 1000
[CURRENCY] US
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   OTHER
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             APR-20-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                           232879
[INVESTMENTS-AT-VALUE]                          241691
[RECEIVABLES]                                    33858
[ASSETS-OTHER]                                      42
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                                  275591
[PAYABLE-FOR-SECURITIES]                         30190
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                         1056
[TOTAL-LIABILITIES]                              31246
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                        220564
[SHARES-COMMON-STOCK]                            19066
[SHARES-COMMON-PRIOR]                                0
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                              29
[ACCUMULATED-NET-GAINS]                          14760
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                          9050
[NET-ASSETS]                                    205657
[DIVIDEND-INCOME]                                 1184
[INTEREST-INCOME]                                  165
[OTHER-INCOME]                                       9
[EXPENSES-NET]                                     215
[NET-INVESTMENT-INCOME]                           1143
[REALIZED-GAINS-CURRENT]                         15845
[APPREC-INCREASE-CURRENT]                         9050
[NET-CHANGE-FROM-OPS]                            26038
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                          962
[DISTRIBUTIONS-OF-GAINS]                           907
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                          20969
[NUMBER-OF-SHARES-REDEEMED]                       2058
[SHARES-REINVESTED]                                155
[NET-CHANGE-IN-ASSETS]                          244345
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                            0
[OVERDISTRIB-NII-PRIOR]                              0
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               20
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                    215
[AVERAGE-NET-ASSETS]                            113560
[PER-SHARE-NAV-BEGIN]                            10.00
[PER-SHARE-NII]                                  0.053
[PER-SHARE-GAIN-APPREC]                          0.840
[PER-SHARE-DIVIDEND]                             0.053
[PER-SHARE-DISTRIBUTIONS]                        0.050
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              10.79
[EXPENSE-RATIO]                                   0.25
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 072
   [NAME] VANGUARD MID-CAP INDEX FUND-INSTITUTIONAL SHARES
[MULTIPLIER] 1000
[CURRENCY] US
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   OTHER
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             MAY-20-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                           232879
[INVESTMENTS-AT-VALUE]                          241691
[RECEIVABLES]                                    33858
[ASSETS-OTHER]                                      42
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                                  275591
[PAYABLE-FOR-SECURITIES]                         30190
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                         1056
[TOTAL-LIABILITIES]                              31246
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                        220564
[SHARES-COMMON-STOCK]                             3586
[SHARES-COMMON-PRIOR]                                0
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                              29
[ACCUMULATED-NET-GAINS]                          14760
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                          9050
[NET-ASSETS]                                     38688
[DIVIDEND-INCOME]                                 1184
[INTEREST-INCOME]                                  165
[OTHER-INCOME]                                       9
[EXPENSES-NET]                                     215
[NET-INVESTMENT-INCOME]                           1143
[REALIZED-GAINS-CURRENT]                         15845
[APPREC-INCREASE-CURRENT]                         9050
[NET-CHANGE-FROM-OPS]                            26038
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                          210
[DISTRIBUTIONS-OF-GAINS]                           178
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                           3559
[NUMBER-OF-SHARES-REDEEMED]                          0
[SHARES-REINVESTED]                                 27
[NET-CHANGE-IN-ASSETS]                          244345
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                            0
[OVERDISTRIB-NII-PRIOR]                              0
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               20
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                    215
[AVERAGE-NET-ASSETS]                             25293
[PER-SHARE-NAV-BEGIN]                            10.03
[PER-SHARE-NII]                                  0.055
[PER-SHARE-GAIN-APPREC]                          0.814
[PER-SHARE-DIVIDEND]                             0.059
[PER-SHARE-DISTRIBUTIONS]                        0.050
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                              10.79
[EXPENSE-RATIO]                                   0.12
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 081
   [NAME] VANGUARD SMALL-CAP VALUE INDEX FUND-INVESTOR SHARES
[MULTIPLIER] 1000
[CURRENCY] US
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   OTHER
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             APR-20-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                           131281
[INVESTMENTS-AT-VALUE]                          119913
[RECEIVABLES]                                    15221
[ASSETS-OTHER]                                      21
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                                  135155
[PAYABLE-FOR-SECURITIES]                         19053
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                         3537
[TOTAL-LIABILITIES]                              22590
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                        123517
[SHARES-COMMON-STOCK]                            12885
[SHARES-COMMON-PRIOR]                                0
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                              66
[ACCUMULATED-NET-GAINS]                            482
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                       (11368)
[NET-ASSETS]                                    112565
[DIVIDEND-INCOME]                                  642
[INTEREST-INCOME]                                  103
[OTHER-INCOME]                                      33
[EXPENSES-NET]                                     139
[NET-INVESTMENT-INCOME]                            639
[REALIZED-GAINS-CURRENT]                           482
[APPREC-INCREASE-CURRENT]                      (11368)
[NET-CHANGE-FROM-OPS]                          (10247)
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                          705
[DISTRIBUTIONS-OF-GAINS]                             0
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                          15327
[NUMBER-OF-SHARES-REDEEMED]                       2516
[SHARES-REINVESTED]                                 74
[NET-CHANGE-IN-ASSETS]                          112565
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                            0
[OVERDISTRIB-NII-PRIOR]                              0
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               20
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                    139
[AVERAGE-NET-ASSETS]                             80848
[PER-SHARE-NAV-BEGIN]                            10.00
[PER-SHARE-NII]                                  0.045
[PER-SHARE-GAIN-APPREC]                        (1.250)
[PER-SHARE-DIVIDEND]                             0.055
[PER-SHARE-DISTRIBUTIONS]                            0
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                               8.74
[EXPENSE-RATIO]                                   0.25
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>

<PAGE>   1
[ARTICLE] 6
[CIK] 0000036405
[NAME] VANGUARD INDEX FUNDS
[SERIES]
   [NUMBER] 091
   [NAME] VANGUARD SMALL-CAP GROWTH INDEX FUND-INVESTOR SHARES
[MULTIPLIER] 1000
[CURRENCY] US
<TABLE>
<S>                             <C>
[PERIOD-TYPE]                   OTHER
[FISCAL-YEAR-END]                          DEC-31-1998
[PERIOD-START]                             APR-20-1998
[PERIOD-END]                               DEC-31-1998
[EXCHANGE-RATE]                                      1
[INVESTMENTS-AT-COST]                            85766
[INVESTMENTS-AT-VALUE]                           91324
[RECEIVABLES]                                    12618
[ASSETS-OTHER]                                      14
[OTHER-ITEMS-ASSETS]                                 0
[TOTAL-ASSETS]                                  103956
[PAYABLE-FOR-SECURITIES]                         11177
[SENIOR-LONG-TERM-DEBT]                              0
[OTHER-ITEMS-LIABILITIES]                         2661
[TOTAL-LIABILITIES]                              13838
[SENIOR-EQUITY]                                      0
[PAID-IN-CAPITAL-COMMON]                         90155
[SHARES-COMMON-STOCK]                             9451
[SHARES-COMMON-PRIOR]                                0
[ACCUMULATED-NII-CURRENT]                            0
[OVERDISTRIBUTION-NII]                              28
[ACCUMULATED-NET-GAINS]                         (5567)
[OVERDISTRIBUTION-GAINS]                             0
[ACCUM-APPREC-OR-DEPREC]                          5558
[NET-ASSETS]                                     90118
[DIVIDEND-INCOME]                                  226
[INTEREST-INCOME]                                   88
[OTHER-INCOME]                                      38
[EXPENSES-NET]                                      99
[NET-INVESTMENT-INCOME]                            253
[REALIZED-GAINS-CURRENT]                        (5567)
[APPREC-INCREASE-CURRENT]                         5558
[NET-CHANGE-FROM-OPS]                              244
[EQUALIZATION]                                       0
[DISTRIBUTIONS-OF-INCOME]                          281
[DISTRIBUTIONS-OF-GAINS]                             0
[DISTRIBUTIONS-OTHER]                                0
[NUMBER-OF-SHARES-SOLD]                          10819
[NUMBER-OF-SHARES-REDEEMED]                       1393
[SHARES-REINVESTED]                                 25
[NET-CHANGE-IN-ASSETS]                           90118
[ACCUMULATED-NII-PRIOR]                              0
[ACCUMULATED-GAINS-PRIOR]                            0
[OVERDISTRIB-NII-PRIOR]                              0
[OVERDIST-NET-GAINS-PRIOR]                           0
[GROSS-ADVISORY-FEES]                               20
[INTEREST-EXPENSE]                                   0
[GROSS-EXPENSE]                                     99
[AVERAGE-NET-ASSETS]                             57505
[PER-SHARE-NAV-BEGIN]                            10.00
[PER-SHARE-NII]                                   0.03
[PER-SHARE-GAIN-APPREC]                         (0.47)
[PER-SHARE-DIVIDEND]                              0.03
[PER-SHARE-DISTRIBUTIONS]                            0
[RETURNS-OF-CAPITAL]                                 0
[PER-SHARE-NAV-END]                               9.53
[EXPENSE-RATIO]                                   0.25
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0
</TABLE>


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