Vanguard Growth Index Fund VIGIX

As with any investment, an investment in the Fund could lose money over any time period. The Fund's share price and total return may fluctuate, potentially within a wide range. The principal risks of investing in the Fund are summarized below. Each of the following risks could affect the Fund's performance:

•  General Market Risk. The markets in which the Fund invests can be affected by a variety of factors. These factors, which can be real or perceived, may include economic, market, political, and regulatory conditions and developments as well as local, regional, or global events such as wars, military conflicts, natural disasters, and public health issues. In addition, investor sentiment and expectations regarding these factors can also impact the markets. Different parts of the market, including different industries and sectors as well as different types of securities, may react differently to factors that affect the market. These factors can contribute to market uncertainty, market volatility, and fluctuations in the value of the Fund's investments, thereby resulting in potential losses to the Fund over short or long periods.

•  Investing in Equity Markets. The Fund invests in the equity markets. Equity markets have historically been cyclical, having periods of time when stock values rise and fall. Market volatility can lead to significant fluctuations in stock values, resulting in potential losses to the Fund.

2

•  Market Capitalization (Market Cap). Companies are generally classified into three types of market cap depending on their size: small-, mid-, and large-cap. Companies can be further classified into micro- or mega-cap. Different factors can affect each market cap uniquely, and historically small- and mid-cap stocks have typically been more volatile due to the effects of changing economic conditions. Large companies may not reach the same levels of growth or performance as smaller companies, and they may be slower to react to competitive challenges. The performance of funds that invest in a subset of market caps could diverge from the performance of a fund that is focused on a broader representation of the stock market.

•  Growth Investing. The Fund's approach to growth investing could cause it to underperform other stock funds that use a different investment style. Growth stocks typically produce lower yields because growth companies prefer to reinvest earnings into research and development to promote growth and increase profitability. Research and development can be expensive and may not always produce favorable results, which could harm a company's performance relative to the broader market.

•  Index Investing. The Fund is subject to risks associated with index investing. Because the Fund generally seeks to track the performance of the Target Index regardless of how the Target Index is performing, the Fund's performance may be lower than it would be if it were actively managed. Although the Fund seeks to hold substantially all of the securities included in the Target Index, it may be unable to do so. In addition, the Fund could be prevented from holding one or more securities in the same proportion as in the Target Index. The performance of the Fund's investments, in the aggregate, may not match the investment performance of the Target Index. This risk, known as tracking error risk, may be heightened during times of increased market volatility or under other unusual market conditions. The Fund also could be negatively impacted by changes to the Target Index made by the index provider or by 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.

•  Nondiversification. By tracking its broad-based Target Index, the Fund could become nondiversified, as defined under the Investment Company Act of 1940, due to events such as an index rebalance or market movement. The performance of nondiversified funds may be negatively impacted by relatively few securities or even a single security and their shares may experience significant fluctuations in value.

•  Concentration Risk. Except as may be necessary to approximate the composition of its Target Index, the Fund will not concentrate its investments in the securities of issuers whose principal business activities are in the same industry or group of industries. If the Target Index becomes concentrated and the Fund needs to concentrate in the same industry or group of industries, its performance could be negatively impacted by the industry or industries in which it is concentrated.

•  Information Technology Sector. As of the Fund's most recent fiscal year end, stocks of companies within the IT sector made up a significant portion of the Target Index. As a result, the performance of the Target Index, and

3

therefore the performance of the Fund, may be impacted by the general condition of the IT sector.

•  ETF Share Trading. Vanguard ETF Shares ("ETF Shares") are an exchanged-traded class of shares issued by certain Vanguard funds that represent an interest in the portfolio of securities held by the issuing fund. The Fund's ETF Shares are listed for trading on NYSE Arca and individual investors may only buy and sell them on the secondary market at market prices. Although it is expected that the market price of an ETF Share typically will approximate its net asset value (NAV), there may be times when the market price of an ETF Share and its NAV differ significantly. Disruptions to creation and redemption transactions, the existence of significant market volatility, or potential lack of an active trading market for ETF Shares (including through a trading halt), as well as other factors, may result in ETF Shares trading significantly above (at a premium) or below (at a discount) the Fund's NAV or the intraday value of the Fund's holdings. Thus, you may pay more or less than NAV when you buy ETF Shares on the secondary market, and you may receive more or less than NAV when you sell those shares.

•  Authorized Participants. Only Authorized Participants may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of financial institutions that may act as Authorized Participants. The Fund's Authorized Participants are not obligated to engage in creation or redemption transactions. To the extent that the Fund's Authorized Participants are unable to or choose not to proceed with creation and/or redemption transactions with respect to the Fund and no other Authorized Participants step forward to engage in creation or redemption transactions with the Fund, the Fund's ETF Shares may trade at a discount to NAV and possibly face trading halts and/or delisting.

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 show the Fund's historical performance and are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund's ETF Shares (based on NAV) has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the ETF Shares compare with those of a broad-based securities market index and one or more additional indexes with similar investment characteristics as 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.

4

Annual Total Returns - Vanguard Growth Index Fund ETF Shares

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

Total Return

Quarter

Highest

29.04

%

June 30, 2020

Lowest

-22.42

%

June 30, 2022

Average Annual Total Returns for Periods Ended December 31, 2025

1 Year

5 Years

10 Years

Vanguard Growth Index Fund ETF Shares

Based on NAV

Return Before Taxes

19.44

%

14.63

%

17.45

%

Return After Taxes on Distributions

19.31

14.48

17.20

Return After Taxes on Distributions and Sale of

Fund Shares

11.58

11.75

14.85

Based on Market Price

Return Before Taxes

19.40

14.62

17.45

CRSP US Large Cap Growth Index

(reflects no deduction for fees, expenses, or taxes)

19.48

%

14.67

%

17.49

%

Dow Jones U.S. Total Stock Market Float Adjusted

Index

(reflects no deduction for fees, expenses, or taxes)

17.05

13.07

14.21

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.

5

Investment Advisor

The Vanguard Group, Inc. (Vanguard) through its wholly owned subsidiary, Vanguard Portfolio Management (VPM). VPM exercises portfolio management responsibilities for the Fund.

Portfolio Managers

Aaron Choi, CFA, Portfolio Manager at VPM. He has co-managed the Fund since 2025.

Gerard C. O'Reilly, Principal of Vanguard and Portfolio Manager at VPM. He has managed the Fund since 1994 (co-managed since 2016).

Jena Stenger, Portfolio Manager at VPM. She has co-managed the Fund since 2025