Summary Prospectus by Investment Company - Form 497K

Vanguard Mega Cap Growth Index Fund

Summary Prospectus

 November 22, 2024

Institutional Shares

Vanguard Mega Cap Growth Index Fund Institutional Shares (VMGAX)

 The Fund's statutory Prospectus and Statement of Additional Information dated November 22, 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 large-capitalization growth stocks in the United States.

Fees and Expenses

The following tables describe the fees and expenses you may pay if you buy, hold, and sell Institutional 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 example below.

Shareholder Fees
(Fees paid directly from your investment) 

Sales Charge (Load) Imposed on Purchases	None
Purchase Fee	None
Sales Charge (Load) Imposed on Reinvested Dividends	None
Redemption Fee	None

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

Management Fees	0.06 %
12b-1 Distribution Fee	None
Other Expenses	0.00 %
Total Annual Fund Operating Expenses	0.06 %

Example

The following example is intended to help you compare the cost of investing in the Fund's Institutional Shares with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you were to invest $10,000 in the Fund's shares. This example assumes 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
$6	$19	$34	$77

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 example, reduce the Fund's performance. During the fiscal period ended September 30, 2024, the Fund's portfolio turnover rate was 21% 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 Mega Cap Growth Index (the Index), which represents the growth companies as determined by the index provider, of the CRSP US Mega Cap Index. The Index is a float-adjusted, market-capitalization-weighted index designed to measure equity market performance of mega-capitalization growth stocks in the United States. 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. The Fund may become nondiversified, as defined under the Investment Company Act of 1940, solely as a result of a change in relative market capitalization or index weighting of one or more constituents of 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.

• Asset concentration risk, which is the chance that, because the Fund tends to invest a high percentage of assets in its ten largest holdings, the Fund's performance may be hurt disproportionately by the poor performance of relatively few stocks.

• Investment style risk, which is the chance that returns from large-capitalization growth stocks in which the Fund invests will trail returns from the overall stock market. Large-cap stocks and growth stocks tend to go through cycles of doing better or worse than other segments of the stock market or the stock market in general. These periods have, in the past, lasted for as long as several years.

• Index-related risks. The Fund is subject to risks associated with index investing, which include passive management risk, tracking error risk, and index provider risk. Passive management risk is the chance that the Fund's use of an indexing strategy will negatively impact the Fund's performance. Because the Fund seeks to track the performance of its target index regardless of how that index is performing, the Fund's performance may be lower than it would be if the Fund were actively managed. Tracking error risk is the chance that the Fund's performance will deviate from the performance of its target index. Tracking error risk may be heightened during times of increased market volatility or under other unusual market conditions. Index provider risk is the chance that the Fund will be negatively impacted by changes or errors made by the index provider. Any gains, losses, or costs associated with or resulting from an error made by the index provider will generally be borne by the Fund and, as a result, the Fund's shareholders.

• 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.

• Nondiversification risk. Because the Fund seeks to closely track the composition of the Fund's target index, from time to time, more than 25% of the Fund's total assets may be invested in issuers representing more than 5% of the Fund's total assets due to an index rebalance or market movement, which would result in the Fund being nondiversified under the Investment Company Act of 1940. The Fund's performance may be hurt disproportionately by the poor performance of relatively few stocks, or even a single stock, and the Fund's shares may experience significant fluctuations in value.

• Sector risk, which is the chance that significant problems will affect a particular sector, or that returns from that sector will trail returns from the overall stock market. Daily fluctuations in specific market sectors are often more extreme or volatile than fluctuations in the overall market. Because a significant portion of the Fund's assets are invested in the information technology sector, the Fund's performance is impacted by the general condition of that sector. Companies in the information technology sector could be affected by, among other things, overall economic conditions, short product cycles, rapid obsolescence of products, competition, and government regulation. Sector risk is expected to be high for the Fund.

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 Institutional Shares compare with those of the Fund's target index and other comparative indexes, which have investment characteristics similar to those of the Fund. The Spliced Mega Cap Growth Index reflects the performance of the MSCI US Large Cap Growth Index through April 16, 2013, and the CRSP US Mega Cap Growth Index thereafter. 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.

Annual Total Returns - Vanguard Mega Cap Growth Index Fund Institutional Shares1  

1 The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2024, was 24.50%.

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

	Total Return	Quarter
Highest	28.81 %	June 30, 2020
Lowest	-22.54 %	June 30, 2022

Average Annual Total Returns for Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years
Vanguard Mega Cap Growth Index Fund Institutional Shares
Return Before Taxes	51.58 %	20.22 %	14.76 %
Return After Taxes on Distributions	51.38	20.02	14.49
Return After Taxes on Distributions and Sale of Fund Shares	30.65	16.50	12.40
Spliced Mega Cap Growth Index (reflects no deduction for fees, expenses, or taxes)	51.67 %	20.28 %	14.82 %
CRSP US Mega Cap Growth Index (reflects no deduction for fees, expenses, or taxes)	51.67	20.28	14.82
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 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

Michelle Louie, CFA, Portfolio Manager and Principal of Vanguard. She has co-managed the Fund since 2021.

Gerard C. O'Reilly, Portfolio Manager and Principal of Vanguard. He has co-managed the Fund since 2015.