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Institutional | Vanguard Mega Cap Growth Index Fund

Vanguard Mega Cap Growth Index Fund

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 table describes the fees and expenses you may pay if you buy and hold Institutional Shares of the Fund.

Shareholder Fees (Fees paid directly from your investment)

Shareholder Fees	Institutional Vanguard Mega Cap Growth Index Fund Institutional Shares
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)

Annual Fund Operating Expenses	Institutional Vanguard Mega Cap Growth Index Fund Institutional Shares
Management Fees	0.06%
12b-1 Distribution Fee	none
Other Expenses	none	[1]
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:

Expense Example	1 Year	3 Years	5 Years	10 Years
Institutional | Vanguard Mega Cap Growth Index Fund | Institutional Shares | USD ($)	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 most recent fiscal year, the Fund's portfolio turnover rate was 14% 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, which represents the growth companies as determined by the index sponsor, 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.

• 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 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.

• Nondiversification risk. Due to a recent index rebalance and in order to closely track the composition of the Fund's target index, more than 25% of the Fund's total assets are invested in issuers representing more than 5% of the Fund's total assets. As a result, the Fund is nondiversified under the Investment Company Act of 1940, although it continues to hold more than 100 stocks across a number of sectors. 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 or by calling Vanguard toll-free at 800-662-7447.

Annual Total Returns — Vanguard Mega Cap Growth Index Fund Institutional Shares

During the periods shown in the bar chart, the highest return for a calendar quarter was 15.27% (quarter ended June 30, 2009), and the lowest return for a quarter was –16.46% (quarter ended December 31, 2018).

Average Annual Total Returns for Periods Ended December 31, 2018

Average Annual Total Returns - Institutional - Vanguard Mega Cap Growth Index Fund		1 Year	5 Years	10 Years
Institutional Shares		(2.85%)	9.56%	14.62%
Institutional Shares | Return After Taxes on Distributions		(3.09%)	9.21%	14.31%
Institutional Shares | Return After Taxes on Distributions and Sale of Fund Shares		(1.49%)	7.53%	12.34%
MSCI US Large Cap Growth Index	[1]	(1.39%)	10.37%	15.10%
Spliced Mega Cap Growth Index	[1]	(2.85%)	9.61%	14.71%
CRSP US Mega Cap Growth Index	[1]	(2.85%)	9.61%

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.

[1] 0.00%

[1] The year-to-date return as of the most recent calendar quarter, which ended on September 30, 2019, was 24.53%.

[1] Comparative Indexes (reflect no deduction for fees, expenses, or taxes)