Summary Prospectus by Investment Company - Form 497K

Vanguard Small-Cap Index Fund

Summary Prospectus

April 26, 2024

Institutional Shares & Institutional Plus Shares

Vanguard Small-Cap Index Fund Institutional Shares (VSCIX)
Vanguard Small-Cap Index Fund Institutional Plus Shares (VSCPX)

The Fund's statutory Prospectus and Statement of Additional Information dated April 26, 2024, as may be amended or supplemented, 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 and https://personal.vanguard.com/us/literature/reports/MFs. You can also obtain this information at no cost by calling 800-662-7447 (if you are an individual investor) or 888-809-8102 (if you are a client of Vanguard's Institutional Division) or by sending an email request to [email protected].

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-capitalization stocks.

Fees and Expenses

The following tables describe the fees and expenses you may pay if you buy, hold, and sell Institutional Shares or Institutional Plus Shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.

Shareholder Fees
(Fees paid directly from your investment)

	Institutional Shares	Institutional Plus 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

Annual Fund Operating Expenses
(Expenses that you pay each year as a percentage of the value of your investment)

	Institutional Shares	Institutional Plus Shares
Management Fees	0.03 %	0.03%
12b-1 Distribution Fee	None	None
Other Expenses	0.01 %	0.00%
Total Annual Fund Operating Expenses	0.04 %	0.03%

Examples

The following examples are intended to help you compare the cost of investing in the Fund's Institutional Shares or Institutional Plus Shares with the cost of investing in other mutual funds. They illustrate the hypothetical expenses that you would incur over various periods if you were to invest $10,000 in the Fund's shares. These examples assume that the shares provide a return of 5% each year and that total annual fund operating expenses remain as stated in the preceding table. You would incur these hypothetical expenses whether or not you were to 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
Institutional Shares	$4	$13	$23	$51
Institutional Plus Shares	$3	$10	$17	$39

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 more 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 12% of the average value of its portfolio.

Principal Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the CRSP US Small Cap Index (the Index), a broadly diversified index of stocks of small U.S. companies. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Principal Risks

An investment in the Fund could lose money over short or long periods of time.You should expect the Fund's share price and total return to fluctuate within a wide range. The Fund is subject to the following risks, which could affect the Fund's performance:

• 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 tracks a subset of the U.S. stock market,

which could cause the Fund to perform differently from the overall stock market. In addition, the Fund's target index may, at times, become focused in stocks of a particular market sector, which would subject the Fund to proportionately higher exposure to the risks of that sector.

• Investment style risk, which is the chance that returns from small-capitalization stocks will trail returns from the overall stock market. Historically, small-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently. The stock prices of small companies tend to experience greater volatility because, among other things, these companies tend to be more sensitive to changing economic conditions.

• Index replicating risk, which is the chance that the Fund may be prevented from holding one or more securities in the same proportion as in its target index.

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 Institutional 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.

Annual Total Returns - Vanguard Small-Cap Index Fund Institutional Shares

During the periods shown in the bar chart, the highest and lowest returns for a calendar quarter were:

	Total Return	Quarter
Highest	27.10 %	December 31, 2020
Lowest	-30.08 %	March 31, 2020

Average Annual Total Returns for Periods Ended December 31, 2023

	1 Year	5 Years	10 Years
Vanguard Small-Cap Index Fund Institutional Shares
Return Before Taxes	18.22 %	11.72 %	8.44 %
Return After Taxes on Distributions	17.66	11.27	7.99
Return After Taxes on Distributions and Sale of Fund Shares	10.99	9.24	6.73
Vanguard Small-Cap Index Fund Institutional Plus Shares
Return Before Taxes	18.22 %	11.73 %	8.46 %
CRSP US Small Cap Index (reflects no deduction for fees, expenses, or taxes)	18.09 %	11.66 %	8.41 %
Dow Jones U.S. Total Stock Market Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	26.06	15.05	11.40

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 Institutional 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, figures captioned Return After Taxes on Distributions and Sale of Fund Shares may 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. (Vanguard)

Portfolio Managers

Kenny Narzikul, CFA, Portfolio Manager at Vanguard. He has co-managed the Fund since 2023.

Gerard C. O'Reilly, Portfolio Manager and Principal of Vanguard. He has co-managed the Fund since 2016.

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 982901, El Paso, TX 79998-2901), or by telephone (800-662-2739). The minimum investment amount required to open and maintain a Fund account for Institutional Shares or Institutional Plus Shares is $5 million or $100 million, respectively. The minimum investment amount required to add to an existing Fund account is generally $1. If you are investing through an employer-sponsored retirement or savings plan, your plan administrator or your benefits office can provide you with detailed information on how you can invest through your plan.

Tax Information

The Fund's distributions may be taxable as ordinary income or capital gain. If you are investing through a tax-advantaged account, such as an IRA or an employer-sponsored retirement or savings plan, special tax rules apply.

Payments to Financial Intermediaries

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