Vanguard Extended Market Index Fund 

Summary Prospectus 

September 27, 2011 

Investor Shares & Admiral™ Shares 

Vanguard Extended Market Index Fund Investor Shares (VEXMX) 

Vanguard Extended Market Index Fund Admiral Shares (VEXAX) 

The Fund’s statutory Prospectus and Statement of Additional Information dated 

September 27, 2011, are incorporated into and made part of this Summary 

Prospectus by reference. 

Before you invest, you may want to review the Fund’s Prospectus, which 

contains more information about the Fund and its risks. You can find 

the Fund’s Prospectus and other information about the Fund online at 

www.vanguard.com/prospectus. You can also get this information at no 

cost by calling 800-662-7447 or by sending an e-mail request to 

online@vanguard.com. 

The Securities and Exchange Commission (SEC) has not approved or disapproved these securities or 

passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense. 

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

Fees and Expenses
The following table describes the fees and expenses you may pay if you buy and hold
Investor Shares or Admiral Shares of the Fund. “Acquired Fund Fees and Expenses”
are expenses incurred indirectly by the Fund through its ownership of shares in other
investment companies, such as business development companies. These expenses
are similar to the expenses paid by any operating company held by the Fund. They are
not direct costs paid by Fund shareholders and are not used to calculate the Fund’s
net asset value. They have no impact on the costs associated with fund operations.
Acquired Fund Fees and Expenses are not included in the Fund’s financial statements,
which provide a clearer picture of a fund’s actual operating costs.

Shareholder Fees
(Fees paid directly from your investment)
	Investor Shares	Admiral Shares
Sales Charge (Load) Imposed on Purchases	None	None
Purchase Fee	None	None
Sales Charge (Load) Imposed on Reinvested Dividends	None	None
Redemption Fee	None	None
Account Service Fee (for fund account balances below $10,000)	$20/year	$20/year
Annual Fund Operating Expenses
(Expenses that you pay each year as a percentage of the value of your investment)
	Investor Shares	Admiral Shares
Management Expenses	0.23%	0.10%
12b-1 Distribution Fee	None	None
Other Expenses	0.03%	0.02%
Acquired Fund Fees and Expenses	0.04%	0.04%
Total Annual Fund Operating Expenses	0.30%	0.16%

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Examples

The following examples are intended to help you compare the cost of investing in the
Fund’s Investor Shares or Admiral Shares with the cost of investing in other mutual
funds. They illustrate the hypothetical expenses that you would incur over various
periods if you invest $10,000 in the Fund’s shares. These examples assume that the
Shares provide a return of 5% a year and that operating expenses remain as stated in
the preceding table. The results apply whether or not you redeem your investment at
the end of the given period. Although your actual costs may be higher or lower, based
on these assumptions your costs would be:

	1 Year	3 Years	5 Years	10 Years
Investor Shares	$31	$97	$169	$381
Admiral Shares	$16	$52	$90	$205

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells
securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate
higher transaction costs and may result in higher taxes when Fund shares are held in
a taxable account. These costs, which are not reflected in annual fund operating
expenses or in the previous expense examples, reduce the Fund’s performance.
During the most recent fiscal year, the Fund’s portfolio turnover rate was 10%.

Primary Investment Strategies
The Fund employs a “passive management”—or indexing—investment approach
designed to track the performance of the Standard & Poor‘s Completion Index, a
broadly diversified index of stocks of small and medium-size U.S. companies. The S&P
Completion Index contains all of the U.S. common stocks regularly traded on the New
York Stock Exchange and the Nasdaq over-the-counter market, except those stocks
included in the S&P 500 Index. The Fund invests all, or substantially all, of its assets in
stocks of its target index, with nearly 80% of its assets invested in approximately
1,200 of the stocks in its target index (covering nearly 85% of the Index’s total market
capitalization), and the rest of its assets in a representative sample of the remaining
stocks. The Fund holds a broadly diversified collection of securities that, in the
aggregate, approximates the full Index in terms of key characteristics. These key
characteristics include industry weightings and market capitalization, as well as
certain financial measures, such as price/earnings ratio and dividend yield.

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Primary Risks
An investment in the Fund could lose money over short or even long periods. You should
expect the Fund’s share price and total return to fluctuate within a wide range, like the
fluctuations of the overall stock market. The Fund’s performance could be hurt by:

• Stock market risk, which is the chance that stock prices overall will decline. Stock
markets tend to move in cycles, with periods of rising prices and periods of falling prices.
The Fund’s target index may, at times, become focused in stocks of a particular sector,
category, or group of companies. Because the Fund seeks to track its target index, the
Fund may underperform the overall stock market.

• Investment style risk, which is the chance that returns from small- and mid-
capitalization stocks will trail returns from the overall stock market. Historically, small-
and mid-cap stocks have been more volatile in price than the large-cap stocks that
dominate the overall market, and they often perform quite differently.

• Index sampling risk, which is the chance that the securities selected for the Fund, in
the aggregate, will not provide investment performance matching that of the Fund’s
target index. Index sampling risk for the Fund should be low.

An investment in the Fund is not a deposit of a bank and is not insured or guaranteed
by the Federal Deposit Insurance Corporation or any other government agency.

Annual Total Returns
The following bar chart and table are intended to help you understand the risks of
investing in the Fund. The bar chart shows how the performance of the Fund‘s
Investor Shares has varied from one calendar year to another over the periods shown.
The table shows how the average annual total returns of the share classes presented
compare with those of the Fund‘s target index and other comparative indexes, which
have investment characteristics similar to those of the Fund. Keep in mind that the
Fund’s past performance (before and after taxes) does not indicate how the Fund will
perform in the future. Updated performance information is available on our website at
vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.

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Annual Total Returns — Vanguard Extended Market Index Fund Investor Shares

During the periods shown in the bar chart, the highest return for a calendar quarter was 21.69% (quarter ended June 30, 2009), and the lowest return for a quarter was –26.60% (quarter ended December 31, 2008).

Average Annual Total Returns for Periods Ended December 31, 2010
	1 Year	5 Years	10 Years
Vanguard Extended Market Index Fund Investor Shares
Return Before Taxes	27.37%	5.04%	5.98%
Return After Taxes on Distributions	27.16	4.79	5.64
Return After Taxes on Distributions and Sale of Fund Shares	17.96	4.25	5.07
Vanguard Extended Market Index Fund Admiral Shares
Return Before Taxes	27.57%	5.20%	6.11%
Comparative Indexes
(reflect no deduction for fees, expenses, or taxes)
Spliced Dow Jones U.S. Completion Total Stock Market Index	28.62%	5.61%	6.30%
Spliced Extended Market Index	27.46	5.05	6.02
Standard & Poor’s Completion Index	27.46	5.05	—

Actual after-tax returns depend on your tax situation and may differ from those shown in the preceding table. When after-tax returns are calculated, it is assumed that the shareholder was in the highest individual federal marginal income tax bracket at the time of each distribution of income or capital gains or upon redemption. State and local income taxes are not reflected in the calculations. Please note that after-tax returns are shown only for the Investor Shares and may differ for each share class. After-tax returns are not relevant for a shareholder who holds fund shares in a tax-deferred account, such as an individual retirement account or a 401(k) plan. Also,

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figures captioned Return After Taxes on Distributions and Sale of Fund Shares will be
higher than other figures for the same period if a capital loss occurs upon redemption
and results in an assumed tax deduction for the shareholder.

Investment Advisor
The Vanguard Group, Inc.

Portfolio Manager

Donald M. Butler, CFA, Principal of Vanguard. He has managed the Fund since 1997.

Purchase and Sale of Fund Shares
You may purchase or redeem shares online through our website (vanguard.com), by
mail (The Vanguard Group, P.O. Box 1110, Valley Forge, PA 19482-1110), or by telephone
(800-662-2739). The following table provides the Fund’s minimum initial and subsequent
investment requirements.

Account Minimums	Investor Shares	Admiral Shares
To open and maintain an account	$3,000	$10,000
To add to an existing account	$100 (other than by Automatic	$100 (other than by Automatic
	Investment Plan, which	Investment Plan, which
	has no established minimum)	has no established minimum)

Tax Information
The Fund’s distributions may be taxable as ordinary income or capital gain. Distributions
are taxable to you for federal income tax purposes, whether or not you reinvest these
amounts in additional Fund shares. A sale or exchange of Fund shares is a taxable
event, which 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.
Dividend and capital gains distributions that you receive, as well as your gains or losses
from any sale or exchange of Fund shares, may also be subject to state and local
income taxes.

Payments to Financial Intermediaries
The Fund and its investment advisor do not pay financial intermediaries for sales of
Fund shares.

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Vanguard Extended Market Index Fund Investor Shares—Fund Number 98
Vanguard Extended Market Index Fund Admiral Shares—Fund Number 598

CFA^® is a trademark owned by CFA Institute.

Standard & Poor’s^®, S&P ^® , S&P 500 ^®are trademarks of Standard & Poor’s Financial Services LLC (“S&P”) and have been
licensed for use by The Vanguard Group, Inc. The Vanguard ETFs are not sponsored, endorsed, sold, or promoted by S&P or its
Affiliates, and S&P and its Affiliates makes no representation, warranty, or condition regarding the advisability of buying,
selling, or holding units/shares in the ETFs. This fund is not sponsored, endorsed, sold or promoted by Standard & Poor’s and
its affiliates (“S&P”). S&P makes no representation, condition or warranty, express or implied, to the owners of the fund or
any member of the public regarding the advisability of investing in securities generally or in the fund particularly or the ability
of the Standard & Poor’s Completion Index to track the performance of certain financial markets and/or sections thereof and/
or of groups of assets or asset classes. S&P’s only relationship to The Vanguard Group, Inc. is the licensing of certain
trademarks and trade names and of the Standard & Poor’s Completion Index which is determined, composed and calculated
by S&P without regard to The Vanguard Group, Inc. or the fund. S&P has no obligation to take the needs of The Vanguard
Group, Inc. or the owners of the fund into consideration in determining, composing or calculating the Standard & Poor’s
Completion Index. S&P is not responsible for and has not participated in the determination of the prices and amount of the
fund or the timing of the issuance or sale of the fund or in the determination or calculation of the equation by which the fund
shares are to be converted into cash. S&P has no obligation or liability in connection with the administration, marketing, or
trading of the fund. S&P does not guarantee the accuracy and/or the completeness of the Standard & Poor’s Completion
Indexor any data included therein and S&P shall have no liability for any errors, omissions, or interruptions therein. S&P
makes no warranty, condition or representation, express or implied, as to results to be obtained by The Vanguard Group, Inc.,
owners of the fund, or any other person or entity from the use of the Standard & Poor’s Completion Index or any data included
therein. S&P makes no express or implied warranties, representations or conditions, and expressly disclaims all warranties or
conditions of merchantability or fitness for a particular purpose or use and any other express or implied warranty or condition
with respect to the Standard & Poor’s Completion Index or any data included therein. Without limiting any of the foregoing, in
no event shall S&P have any liability for any special, punitive, indirect, or consequential damages (including lost profits)
resulting from the use of the Standard & Poor’s Completion Index or any data included therein, even if notified of the
possibility of such damages.

© 2011 The Vanguard Group, Inc. All rights reserved.
Vanguard Marketing Corporation, Distributor.
	SP 98 092011