Vanguard U.S. Stock Index Small-Capitalization Funds .

ExampleThe following example is intended to help you compare the cost of investing inthe Fund’s Investor Shares with the cost of investing in other mutual funds. Itillustrates the hypothetical expenses that you would incur over various periods ifyou were to invest 10,000 in the Fund’s shares. This example assumes that theshares provide a return of 5% each year and that total annual fund operatingexpenses remain as stated in the preceding table. You would incur thesehypothetical expenses whether or not you were to redeem your investment atthe end of the given period. Although your actual costs may be higher or lower,based on these assumptions your costs would be:1 Year 193 Years 615 Years 10710 Years 243Portfolio TurnoverThe Fund pays transaction costs, such as commissions, when it buys and sellssecurities (or “turns over” its portfolio). A higher portfolio turnover rate mayindicate higher transaction costs and may result in more taxes when Fundshares are held in a taxable account. These costs, which are not reflected inannual fund operating expenses or in the previous expense example, reduce theFund’s performance. During the most recent fiscal year, the Fund’s portfolioturnover rate was 26% of the average value of its portfolio.Principal Investment StrategiesThe Fund employs an indexing investment approach designed to track theperformance of the CRSP US Small Cap Value Index, a broadly diversified indexof value stocks of small U.S. companies. The Fund attempts to replicate thetarget index by investing all, or substantially all, of its assets in the stocks thatmake up the Index, holding each stock in approximately the same proportion asits weighting in the Index.Principal RisksAn 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 awide range. The Fund is subject to the following risks, which could affect theFund’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 periodsof 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 a8

particular market sector, which would subject the Fund to proportionately higherexposure to the risks of that sector. Investment style risk, which is the chance that returns fromsmall-capitalization value stocks will trail returns from the overall stock market.Historically, small-cap stocks have been more volatile in price than the large-capstocks that dominate the overall market, and they often perform quite differently.The stock prices of small companies tend to experience greater volatilitybecause, among other things, these companies tend to be more sensitive tochanging economic conditions.An investment in the Fund is not a deposit of a bank and is not insured orguaranteed by the Federal Deposit Insurance Corporation or any othergovernment agency.Annual Total ReturnsThe following bar chart and table are intended to help you understand the risksof investing in the Fund. The bar chart shows how the performance of the Fund‘sInvestor Shares has varied from one calendar year to another over the periodsshown. The table shows how the average annual total returns of the Fund’sInvestor Shares compare with those of the Fund’s target index and othercomparative indexes, which have investment characteristics similar to those ofthe Fund. The Spliced Small Cap Value Index reflects the performance of theMSCI US Small Cap Value Index through April 16, 2013, and the CRSP US SmallCap Value Index thereafter. Keep in mind that the Fund’s past performance(before and after taxes) does not indicate how the Fund will perform in thefuture. Updated performance information is available on our website atvanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.9

Annual Total Returns — Vanguard Small-Cap Value Index Fund Investor 16–4.78–12.34-40%During the periods shown in the bar chart, the highest and lowest returns for acalendar quarter were:HighestLowestTotal Return29.31%-34.89%QuarterDecember 31, 2020March 31, 2020Average Annual Total Returns for Periods Ended December 31, 20201 Year5 Years10 YearsVanguard Small-Cap Value Index Fund Investor SharesReturn Before TaxesReturn After Taxes on Distributions5.72%5.219.60%9.029.93%9.37Return After Taxes on Distributions and Sale of Fund SharesComparative Indexes(reflect no deduction for fees, expenses, or taxes)Spliced Small Cap Value Index3.597.448.005.75%9.72%CRSP US Small Cap Value IndexDow Jones U.S. Total Stock Market Float Adjusted Index5.7520.799.7215.3610.08%—13.74Actual after-tax returns depend on your tax situation and may differ from thoseshown in the preceding table. When after-tax returns are calculated, it isassumed that the shareholder was in the highest individual federal marginalincome tax bracket at the time of each distribution of income or capital gains orupon redemption. State and local income taxes are not reflected in thecalculations. Please note that after-tax returns are not relevant for a shareholderwho holds fund shares in a tax-deferred account, such as an individual retirementaccount or a 401(k) plan. Also, figures captioned Return After Taxes onDistributions and Sale of Fund Shares may be higher than other figures for thesame period if a capital loss occurs upon redemption and results in an assumedtax deduction for the shareholder.10

Investment AdvisorThe Vanguard Group, Inc. (Vanguard)Portfolio ManagersWilliam A. Coleman, CFA, Portfolio Manager at Vanguard. He has co-managedthe Fund since 2016.Gerard C. O’Reilly, Principal of Vanguard. He has co-managed the Fundsince 2016.Purchase and Sale of Fund SharesYou 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 bytelephone (800-662-2739). Investor Shares are generally available only toVanguard funds that operate as funds of funds and to certain retirement planclients that receive recordkeeping services from Vanguard. Financialintermediaries, institutional clients, and Vanguard-advised clients should contactVanguard for information on special eligibility rules that may apply to themregarding Investor Shares. If you are investing through an intermediary, pleasecontact that firm directly for more information regarding your eligibility. If you areinvesting through an employer-sponsored retirement or savings plan, your planadministrator or your benefits office can provide you with detailed information onhow you can invest through your plan.Tax InformationThe Fund’s distributions may be taxable as ordinary income or capital gain. If youare investing through a tax-advantaged account, such as an IRA or anemployer-sponsored retirement or savings plan, special tax rules apply.Payments to Financial IntermediariesThe Fund and its investment advisor do not pay financial intermediaries for salesof Fund shares.11

Vanguard Small-Cap Growth Index FundInvestment ObjectiveThe Fund seeks to track the performance of a benchmark index that measuresthe investment return of small-capitalization growth stocks.Fees and ExpensesThe following table describes the fees and expenses you may pay if you buy,hold, and sell Investor Shares of the Fund. You may pay other fees, such asbrokerage commissions and other fees to financial intermediaries, which are notreflected in the table and example below.Shareholder Fees(Fees paid directly from your investment)Sales Charge (Load) Imposed on PurchasesPurchase FeeNoneNoneSales Charge (Load) Imposed on Reinvested DividendsRedemption FeeNoneNoneAccount Service Fee Per Year(for certain fund account balances below 10,000) 20Annual Fund Operating Expenses(Expenses that you pay each year as a percentage of the value of your investment)Management Fees0.18%12b-1 Distribution FeeOther ExpensesTotal Annual Fund Operating ExpensesNone0.01%0.19%12

ExampleThe following example is intended to help you compare the cost of investing inthe Fund’s Investor Shares with the cost of investing in other mutual funds. Itillustrates the hypothetical expenses that you would incur over various periods ifyou were to invest 10,000 in the Fund’s shares. This example assumes that theshares provide a return of 5% each year and that total annual fund operatingexpenses remain as stated in the preceding table. You would incur thesehypothetical expenses whether or not you were to redeem your investment atthe end of the given period. Although your actual costs may be higher or lower,based on these assumptions your costs would be:1 Year 193 Years 615 Years 10710 Years 243Portfolio TurnoverThe Fund pays transaction costs, such as commissions, when it buys and sellssecurities (or “turns over” its portfolio). A higher portfolio turnover rate mayindicate higher transaction costs and may result in more taxes when Fundshares are held in a taxable account. These costs, which are not reflected inannual fund operating expenses or in the previous expense example, reduce theFund’s performance. During the most recent fiscal year, the Fund’s portfolioturnover rate was 24% of the average value of its portfolio.Principal Investment StrategiesThe Fund employs an indexing investment approach designed to track theperformance of the CRSP US Small Cap Growth Index, a broadly diversifiedindex of growth stocks of small U.S. companies. The Fund attempts to replicatethe target index by investing all, or substantially all, of its assets in the stocksthat make up the Index, holding each stock in approximately the same proportionas its weighting in the Index.Principal RisksAn 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 awide range. The Fund is subject to the following risks, which could affect theFund’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 periodsof 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 a13

particular market sector, which would subject the Fund to proportionately higherexposure to the risks of that sector. Investment style risk, which is the chance that returns fromsmall-capitalization growth stocks will trail returns from the overall stock market.Historically, small-cap stocks have been more volatile in price than the large-capstocks that dominate the overall market, and they often perform quite differently.The stock prices of small companies tend to experience greater volatilitybecause, among other things, these companies tend to be more sensitive tochanging economic conditions.An investment in the Fund is not a deposit of a bank and is not insured orguaranteed by the Federal Deposit Insurance Corporation or any othergovernment agency.Annual Total ReturnsThe following bar chart and table are intended to help you understand the risksof investing in the Fund. The bar chart shows how the performance of the Fund‘sInvestor Shares has varied from one calendar year to another over the periodsshown. The table shows how the average annual total returns of the Fund’sInvestor Shares compare with those of the Fund’s target index and othercomparative indexes, which have investment characteristics similar to those ofthe Fund. The Spliced Small-Cap Growth Index reflects the performance of MSCIUS Small Cap Growth Index through April 16, 2013, and the CRSP US Small CapGrowth Index thereafter. Keep in mind that the Fund’s past performance (beforeand after taxes) does not indicate how the Fund will perform in the future.Updated performance information is available on our website atvanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.14

Annual Total Returns — Vanguard Small-Cap Growth Index Fund Investor 13.88–1.58–2.64–5.80During the periods shown in the bar chart, the highest and lowest returns for acalendar quarter were:HighestLowestTotal Return32.89%-24.24%QuarterJune 30, 2020March 31, 2020Average Annual Total Returns for Periods Ended December 31, 20201 Year5 Years10 YearsVanguard Small-Cap Growth Index Fund Investor SharesReturn Before TaxesReturn After Taxes on Distributions35.12% 17.85%34.9717.6113.88%13.66Return After Taxes on Distributions and Sale of Fund SharesComparative Indexes(reflect no deduction for fees, expenses, or taxes)Spliced Small Cap Growth Index20.8411.6135.35% 17.97%13.96%CRSP US Small Cap Growth IndexDow Jones U.S. Total Stock Market Float Adjusted Index35.3520.79—13.7414.4117.9715.36Actual after-tax returns depend on your tax situation and may differ from thoseshown in the preceding table. When after-tax returns are calculated, it isassumed that the shareholder was in the highest individual federal marginalincome tax bracket at the time of each distribution of income or capital gains orupon redemption. State and local income taxes are not reflected in thecalculations. Please note that after-tax returns are not relevant for a shareholderwho holds fund shares in a tax-deferred account, such as an individual retirementaccount or a 401(k) plan. Also, figures captioned Return After Taxes onDistributions and Sale of Fund Shares may be higher than other figures for thesame period if a capital loss occurs upon redemption and results in an assumedtax deduction for the shareholder.15

Investment AdvisorThe Vanguard Group, Inc. (Vanguard)Portfolio ManagersWilliam A. Coleman, CFA, Portfolio Manager at Vanguard. He has co-managedthe Fund since 2016.Gerard C. O’Reilly, Principal of Vanguard. He has managed the Fund since 2004(co-managed since 2016).Purchase and Sale of Fund SharesYou 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 bytelephone (800-662-2739). Investor Shares are generally available only toVanguard funds that operate as funds of funds and to certain retirement planclients that receive recordkeeping services from Vanguard. Financialintermediaries, institutional clients, and Vanguard-advised clients should contactVanguard for information on special eligibility rules that may apply to themregarding Investor Shares. If you are investing through an intermediary, pleasecontact that firm directly for more information regarding your eligibility. If you areinvesting through an employer-sponsored retirement or savings plan, your planadministrator or your benefits office can provide you with detailed information onhow you can invest through your plan.Tax InformationThe Fund’s distributions may be taxable as ordinary income or capital gain. If youare investing through a tax-advantaged account, such as an IRA or anemployer-sponsored retirement or savings plan, special tax rules apply.Payments to Financial IntermediariesThe Fund and its investment advisor do not pay financial intermediaries for salesof Fund shares.16

Investing in Index FundsWhat Is Indexing?Indexing is an investment strategy for tracking the performance of a specifiedmarket benchmark, or “index.” An index is a group of securities whose overallperformance is used as a standard to measure the investment performance of aparticular market. There are many types of indexes. Some represent entiremarkets—such as the U.S. stock market or the U.S. bond market. Other indexescover market segments—such as small-capitalization stocks or short-termbonds. One cannot invest directly in an index.The index sponsor determines the securities to include in the index and theweighting of each security in the index. Under normal circumstances, the indexsponsor will rebalance an index on a regular schedule. An index sponsor maycarry out additional ad hoc index rebalances or delay or cancel a scheduledrebalance. Generally, the index sponsor does not provide any warranty, or acceptany liability, with respect to the quality, accuracy, or completeness of either thetarget index or its related data. Errors made by the index sponsor may occurfrom time to time and may not be identified by the index sponsor for a period oftime or at all. Vanguard does not provide any warranty or guarantee against sucherrors. Therefore, the gains, losses, or costs associated with the index sponsor’serrors will generally be borne by the index fund and its shareholders.An index fund seeks to hold all, or a representative sample, of the securities thatmake up its target index. Index funds attempt to mirror the performance of thetarget index, for better or worse. However, an index fund generally does notperform exactly like its target index. For example, index funds have operatingexpenses and transaction costs. Market indexes do not, and therefore they willusually have a slight performance advantage over funds that track them. Theability of an index fund to match its performance to that of its target index canalso be impacted by, among other things, the timing and size of cash flows andthe size of the fund. Market disruptions and regulatory restrictions could alsohave an adverse effect on a fund’s ability to adjust its exposure to the requiredlevels in order to track the index.Index funds typically have the following characteristics: Variety of investments. Depending on a fund’s benchmark index, the fund mayinvest in the securities of a variety of companies, industries, and/or governmentsor government agencies. Relative performance consistency. Because they seek to track marketbenchmarks, index funds usually do not perform dramatically better or worsethan their benchmarks. Low cost. Index funds are generally inexpensive to run compared with activelymanaged funds. They have low or no research costs and typically keep tradingactivity—and thus brokerage commissions and other transaction costs—to aminimum compared with actively managed funds.17

More on the FundsThis prospectus describes the principal risks you would face as a Fundshareholder. It is important to keep in mind one of the main principles ofinvesting: generally, the higher the risk of losing money, the higher the potentialreward. The reverse, also, is generally true: the lower the risk, the lower thepotential reward. As you consider an investment in any mutual fund, you shouldtake into account your personal tolerance for fluctuations in the securitiesmarkets. Look for thissymbol throughout the prospectus. It is used tomark detailed information about the more significant risks that you wouldconfront as a Fund shareholder. To highlight terms and concepts important tomutual fund investors, we have provided Plain Talk explanations along the way.Reading the prospectus will help you decide whether a Fund is the rightinvestment for you. We suggest that you keep this prospectus forfuture reference.Share Class OverviewThis prospectus offers the Funds’ Investor Shares. Another prospectus offers theFunds’ Admiral Shares , which are generally for investors who invest aminimum of 3,000. A separate prospectus offers the Funds’ Institutional Sharesand the Small-Cap I

† 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 di