497

December 19, 2025 (as supplemented on June 30, 2026)

Prospectus

Vanguard Sector Bond ETFs

Exchange-traded fund shares that are not individually redeemable and are listed on Nasdaq

Vanguard Short-Term Treasury Index Fund ETF Shares (VGSH)
Vanguard Intermediate-Term Treasury Index Fund ETF Shares (VGIT)
Vanguard Long-Term Treasury Index Fund ETF Shares (VGLT)
Vanguard Short-Term Corporate Bond Index Fund ETF Shares (VCSH)
Vanguard Intermediate-Term Corporate Bond Index Fund ETF Shares (VCIT)
Vanguard Long-Term Corporate Bond Index Fund ETF Shares (VCLT)
Vanguard Mortgage-Backed Securities Index Fund ETF Shares (VMBS)

This Prospectus contains financial data for the Funds through the fiscal year ended August 31, 2025.

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.

Contents

Fund Summaries
Vanguard Short-Term Treasury ETF	1
Vanguard Intermediate-Term Treasury ETF	8
Vanguard Long-Term Treasury ETF	15
Vanguard Short-Term Corporate Bond ETF	22
Vanguard Intermediate-Term Corporate Bond ETF	29
Vanguard Long-Term Corporate Bond ETF	36
Vanguard Mortgage-Backed Securities ETF	43
More on the Funds	50
Investment Objectives and More on Principal Investment Strategies	51
More on Fund Risks	57
Other Investment Policies	65
Portfolio Holdings	67
Management and Distribution of the Funds	67
Investing in Vanguard ETF® Shares	70
Pricing of Fund Shares	72
Dividends, Distributions, and Taxes	75
Frequent Trading Limitations	77
Financial Highlights	78
Additional Information	85

Vanguard Short-Term Treasury ETF

Investment Objective

Vanguard Short-Term Treasury ETF, an exchange-traded share class of Vanguard Short-Term Treasury Index Fund (the “Fund”), seeks to track the performance of a market-weighted Treasury index with a short-term dollar-weighted average maturity.

Fees and Expenses

The following tables describe the fees and expenses you may pay if you buy, hold, and sell ETF 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)


Transaction Fee on Purchases and Sales	None*
Transaction Fee on Reinvested Dividends	None*
Transaction Fee on Conversion to ETF Shares	None*

None through Vanguard (Broker fees vary)

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


Management Fees	0.02 %
12b-1 Distribution Fee	None
Other Expenses	0.01 %
Total Annual Fund Operating Expenses	0.03 %

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same.

1 Year	3 Years	5 Years	10 Years
$3	$10	$17	$39

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

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 higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 93% of the average value of its portfolio.

Principal Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the Bloomberg U.S. Treasury 1-3 Year Index (the “Target Index”), which includes bonds issued by the U.S. Treasury (not including inflation-protected securities, floating rate securities, and certain other security types), all with maturities between 1 and 3 years. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the bonds that make up the Target Index.

The Fund invests by sampling the Target Index, meaning that it holds a range of securities that, in the aggregate, approximates the full Target Index in terms of key risk factors and other characteristics. The Fund maintains a dollar-weighted average maturity consistent with that of the Target Index. As of August 31, 2025, the dollar-weighted average maturity of the Target Index was 2 years.

Principal Risks

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 Bond Markets. The Fund may be impacted by the general condition of the bond markets and by factors that affect bonds and bond issuers. For example, as a general rule, bond prices and interest rates move in opposite directions. When interest rates rise, bond prices tend to fall, and when interest rates fall, bond prices tend to go up. Bond income also is affected by changes in interest rates. Interest rates can rise or fall for a number of reasons, including, but not limited to, central bank monetary policy, inflationary or deflationary pressures, and changes in general market and economic conditions. Changing interest rates, including, but not limited to, rates that fall below zero, could have unpredictable effects on the overall market and may expose the bond markets in particular to heightened volatility and potential illiquidity. The degree to which the Fund is impacted by certain bond market risks may vary based on factors disclosed in its principal investment strategies, such as the types of bonds in which it invests and the overall credit quality, average maturity, and/or average duration of its bond holdings.

• Interest Rate Risk. During periods of rising interest rates, bond prices overall may decline, which could result in a decline in the Fund’s value. The prices of longer-term bonds are more sensitive to changes in interest rates than the prices of shorter-term bonds.

• Income Risk. During periods of falling interest rates, the Fund’s income may decline. The income paid by shorter-term bonds is subject to a higher degree of fluctuation than the income paid by longer-term bonds.

• Credit Risk. Credit risk refers to the chance that an issuer will default (fail to meet its credit obligations) or fail to make payments in a timely manner, which could result in a loss to the Fund. In addition, negative perceptions of an issuer’s ability to make payments can cause the price of a security to decline. While all debt securities are subject to credit risk to some extent, those with higher credit quality ratings generally pose less credit risk than those with lower credit quality ratings.

• Bond Liquidity Risk. If the Fund is unable to sell a security at an advantageous time or price, its returns may be reduced. There may be limited trading in the secondary market for certain debt securities, which could make them more difficult to value or sell.

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.

• 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 Nasdaq 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. The Spliced Bloomberg U.S. Treasury 1-3 Year Index reflects the performance of the

Bloomberg U.S. 1-3 Year Government Float Adjusted Index through December 11, 2017, and the Bloomberg U.S. Treasury 1-3 Year 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 Short-Term Treasury Index Fund ETF Shares

The highest and lowest returns for a calendar quarter during the periods shown in the bar chart and the year-to-date return as of the most recent calendar quarter were:

	Total Return	Quarter
Highest	2.90 %	September 30, 2024
Lowest	-2.51 %	March 31, 2022
Year-to-Date Return	3.95 %	September 30, 2025

Average Annual Total Returns for Periods Ended December 31, 2024

	1 Year	5 Years	10 Years
Vanguard Short-Term Treasury Index Fund ETF Shares
Based on NAV
Return Before Taxes	4.02 %	1.34 %	1.33 %
Return After Taxes on Distributions	2.26	0.44	0.60
Return After Taxes on Distributions and Sale of Fund Shares	2.36	0.65	0.71
Based on Market Price
Return Before Taxes	4.01	1.33	1.33
Bloomberg U.S. Treasury 1-3 Year Index (reflects no deduction for fees, expenses, or taxes)	4.03 %	1.36 %	1.38 %
Spliced Bloomberg U.S. Treasury 1-3 Year Index in USD (reflects no deduction for fees, expenses, or taxes)	4.03	1.36	1.38
Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	1.33	-0.27	1.39

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) through its wholly owned subsidiary, Vanguard Capital Management (VCM). VCM exercises portfolio management responsibilities for the Fund.

Portfolio Manager

Joshua C. Barrickman, CFA, Principal of Vanguard and Portfolio Manager at VCM. He has managed the Fund since 2013.

Purchase and Sale of Fund Shares

ETF Shares may only be bought and sold in the secondary market through a brokerage firm. The price you pay or receive for ETF Shares will be the prevailing market price, which may be more (premium) or less (discount) than the NAV of the shares. The brokerage firm may charge you a commission to execute the transaction. Unless imposed by your brokerage firm, there is no minimum dollar amount you must invest and no minimum number of shares you must buy. ETF Shares of the Fund cannot be directly purchased from or redeemed with the Fund, except by certain authorized broker-dealers. These broker-dealers may purchase and redeem ETF Shares only in large blocks known as creation units, typically in exchange for baskets of securities.

An investor in ETF Shares may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase ETF Shares (bid) and the lowest price a seller is willing to accept for ETF Shares (ask) when buying or selling shares in the secondary market (bid-ask spread). Recent information about the Fund and its ETF Shares, including information on the Fund’s NAV, market price, premiums and discounts, and bid-ask spreads, is available online at vanguard.com.

Tax Information

The Fund’s distributions may be taxable as ordinary income or capital gains. 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. You should consult your own tax advisor with respect to any particular U.S. or non-U.S. tax consequences of your investment in the Fund.

Payments to Financial Intermediaries

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

Vanguard Intermediate-Term Treasury ETF

Investment Objective

Vanguard Intermediate-Term Treasury ETF, an exchange-traded share class of Vanguard Intermediate-Term Treasury Index Fund (the “Fund”), seeks to track the performance of a market-weighted Treasury index with an intermediate-term dollar-weighted average maturity.

Fees and Expenses

Shareholder Fees
(Fees paid directly from your investment)


Transaction Fee on Purchases and Sales	None*
Transaction Fee on Reinvested Dividends	None*
Transaction Fee on Conversion to ETF Shares	None*

None through Vanguard (Broker fees vary)

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


Management Fees	0.02 %
12b-1 Distribution Fee	None
Other Expenses	0.01 %
Total Annual Fund Operating Expenses	0.03 %

Example

1 Year	3 Years	5 Years	10 Years
$3	$10	$17	$39

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Portfolio Turnover

Principal Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the Bloomberg U.S. Treasury 3-10 Year Index (the “Target Index”), which includes bonds issued by the U.S. Treasury (not including inflation-protected securities, floating rate securities, and certain other security types), all with maturities between 3 and 10 years. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the bonds that make up the Target Index.

Principal Risks

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

Bloomberg U.S. 3-10 Year Government Float Adjusted Index through December 11, 2017, and the Bloomberg U.S. Treasury 3-10 Year 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 Intermediate-Term Treasury Index Fund ETF Shares

The highest and lowest returns for a calendar quarter during the periods shown in the bar chart and the year-to-date return as of the most recent calendar quarter were:

	Total Return	Quarter
Highest	7.09 %	March 31, 2020
Lowest	-5.31 %	March 31, 2022
Year-to-Date Return	6.21 %	September 30, 2025

Average Annual Total Returns for Periods Ended December 31, 2024

	1 Year	5 Years	10 Years
Vanguard Intermediate-Term Treasury Index Fund ETF Shares
Based on NAV
Return Before Taxes	1.32 %	-0.17 %	1.09 %
Return After Taxes on Distributions	-0.17	-1.11	0.23
Return After Taxes on Distributions and Sale of Fund Shares	0.78	-0.49	0.48
Based on Market Price
Return Before Taxes	1.38	-0.17	1.06
Bloomberg U.S. Treasury 3-10 Year Index (reflects no deduction for fees, expenses, or taxes)	1.26 %	-0.16 %	1.14 %
Spliced Bloomberg U.S. Treasury 3-10 Year Index in USD (reflects no deduction for fees, expenses, or taxes)	1.26	-0.16	1.14
Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	1.33	-0.27	1.39

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) through its wholly owned subsidiary, Vanguard Capital Management (VCM). VCM exercises portfolio management responsibilities for the Fund.

Portfolio Manager

Joshua C. Barrickman, CFA, Principal of Vanguard and Portfolio Manager at VCM. He has managed the Fund since 2013.

Purchase and Sale of Fund Shares

Tax Information

Payments to Financial Intermediaries

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

Vanguard Long-Term Treasury ETF

Investment Objective

Vanguard Long-Term Treasury ETF, an exchange-traded share class of Vanguard Long-Term Treasury Index Fund (the “Fund”), seeks to track the performance of a market-weighted Treasury index with a long-term dollar-weighted average maturity.

Fees and Expenses

Shareholder Fees
(Fees paid directly from your investment)


Transaction Fee on Purchases and Sales	None*
Transaction Fee on Reinvested Dividends	None*
Transaction Fee on Conversion to ETF Shares	None*

None through Vanguard (Broker fees vary)

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


Management Fees	0.02 %
12b-1 Distribution Fee	None
Other Expenses	0.01 %
Total Annual Fund Operating Expenses	0.03 %

Example

1 Year	3 Years	5 Years	10 Years
$3	$10	$17	$39

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Portfolio Turnover

Principal Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the Bloomberg U.S. Long Treasury Index (the “Target Index”), which includes bonds issued by the U.S. Treasury (not including inflation-protected securities, floating rate securities, and certain other security types), all with maturities greater than 10 years. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the bonds that make up the Target Index.

Principal Risks

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. The Spliced Bloomberg U.S. Long Treasury Index reflects the performance of the

Bloomberg U.S. Long Government Float Adjusted Index through December 11, 2017, and the Bloomberg U.S. Long Treasury 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 Long-Term Treasury Index Fund ETF Shares

The highest and lowest returns for a calendar quarter during the periods shown in the bar chart and the year-to-date return as of the most recent calendar quarter were:

	Total Return	Quarter
Highest	20.84 %	March 31, 2020
Lowest	-13.45 %	March 31, 2021
Year-to-Date Return	5.68 %	September 30, 2025

Average Annual Total Returns for Periods Ended December 31, 2024

	1 Year	5 Years	10 Years
Vanguard Long-Term Treasury Index Fund ETF Shares
Based on NAV
Return Before Taxes	-6.46 %	-5.21 %	-0.68 %
Return After Taxes on Distributions	-8.01	-6.28	-1.78
Return After Taxes on Distributions and Sale of Fund Shares	-3.79	-4.21	-0.90
Based on Market Price
Return Before Taxes	-6.30	-5.22	-0.69
Bloomberg U.S. Long Treasury Bond Index (reflects no deduction for fees, expenses, or taxes)	-6.41 %	-5.20 %	-0.64 %
Spliced Bloomberg U.S. Long Treasury Index in USD (reflects no deduction for fees, expenses, or taxes)	-6.41	-5.20	-0.62
Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	1.33	-0.27	1.39

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) through its wholly owned subsidiary, Vanguard Capital Management (VCM). VCM exercises portfolio management responsibilities for the Fund.

Portfolio Manager

Joshua C. Barrickman, CFA, Principal of Vanguard and Portfolio Manager at VCM. He has managed the Fund since 2013.

Purchase and Sale of Fund Shares

Tax Information

Payments to Financial Intermediaries

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

Vanguard Short-Term Corporate Bond ETF

Investment Objective

Vanguard Short-Term Corporate Bond ETF, an exchange-traded share class of Vanguard Short-Term Corporate Bond Index Fund (the “Fund”), seeks to track the performance of a market-weighted corporate bond index with a short-term dollar-weighted average maturity.

Fees and Expenses

Shareholder Fees
(Fees paid directly from your investment)


Transaction Fee on Purchases and Sales	None*
Transaction Fee on Reinvested Dividends	None*
Transaction Fee on Conversion to ETF Shares	None*

None through Vanguard (Broker fees vary)

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


Management Fees	0.02 %
12b-1 Distribution Fee	None
Other Expenses	0.01 %
Total Annual Fund Operating Expenses	0.03 %

Example

1 Year	3 Years	5 Years	10 Years
$3	$10	$17	$39

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Portfolio Turnover

Principal Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the Bloomberg U.S. 1-5 Year Corporate Bond Index (the “Target Index”), which includes U.S. dollar-denominated, investment-grade, fixed-rate, taxable debt securities issued by U.S. and non-U.S. industrial, utility, and financial companies, all with maturities between 1 and 5 years. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the bonds that make up the Target Index.

Principal Risks

• Call Risk. Certain bonds held by the Fund may be callable. The issuer of a callable bond has the right to “call” (redeem) the bond before its maturity date. Calls on bonds held by the Fund would result in the Fund losing any price appreciation above the bond’s call price. In addition, because bond calls occur more frequently during periods of falling interest rates, the Fund likely would be forced to reinvest the proceeds of any called bonds at a lower interest rate than that of the called bonds, resulting in a decline in the Fund’s income and a potential loss in the value of the Fund’s investments. Frequent bond calls and subsequent reinvestments of the proceeds also would increase the Fund’s turnover rate.

• 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. Additionally, because the Fund does not hold all of the securities included in the Target Index, it is subject to the risk that the representative sample of securities selected by the advisor will, in the aggregate, vary from the investment profile of the full 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.

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.

Annual Total Returns — Vanguard Short-Term Corporate Bond Index Fund ETF Shares

The highest and lowest returns for a calendar quarter during the periods shown in the bar chart and the year-to-date return as of the most recent calendar quarter were:

	Total Return	Quarter
Highest	5.57 %	June 30, 2020
Lowest	-3.71 %	March 31, 2022
Year-to-Date Return	5.47 %	September 30, 2025

Average Annual Total Returns for Periods Ended December 31, 2024

	1 Year	5 Years	10 Years
Vanguard Short-Term Corporate Bond Index Fund ETF Shares
Based on NAV
Return Before Taxes	4.95 %	1.93 %	2.36 %
Return After Taxes on Distributions	3.27	0.85	1.31
Return After Taxes on Distributions and Sale of Fund Shares	2.91	1.01	1.35
Based on Market Price
Return Before Taxes	4.92	1.90	2.33
Bloomberg U.S. 1-5 Year Corporate Bond Index (reflects no deduction for fees, expenses, or taxes)	4.95 %	1.99 %	2.44 %
Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	1.33	-0.27	1.39

Investment Advisor

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

Portfolio Managers

Joshua C. Barrickman, CFA, Principal of Vanguard and Portfolio Manager at VCM. He has managed the Fund since its inception in 2009 (co-managed since 2025).

Jake Riley, CFA, Portfolio Manager at VCM. He has co-managed the Fund since 2025.

Purchase and Sale of Fund Shares

Tax Information

Payments to Financial Intermediaries

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

Vanguard Intermediate-Term Corporate Bond ETF

Investment Objective

Vanguard Intermediate-Term Corporate Bond ETF, an exchange-traded share class of Vanguard Intermediate-Term Corporate Bond Index Fund (the “Fund”), seeks to track the performance of a market-weighted corporate bond index with an intermediate-term dollar-weighted average maturity.

Fees and Expenses

Shareholder Fees
(Fees paid directly from your investment)


Transaction Fee on Purchases and Sales	None*
Transaction Fee on Reinvested Dividends	None*
Transaction Fee on Conversion to ETF Shares	None*

None through Vanguard (Broker fees vary)

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


Management Fees	0.02 %
12b-1 Distribution Fee	None
Other Expenses	0.01 %
Total Annual Fund Operating Expenses	0.03 %

Example

1 Year	3 Years	5 Years	10 Years
$3	$10	$17	$39

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Portfolio Turnover

Principal Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the Bloomberg U.S. 5-10 Year Corporate Bond Index (the “Target Index”), which includes U.S. dollar-denominated, investment-grade, fixed-rate, taxable debt securities issued by U.S. and non-U.S. industrial, utility, and financial companies, all with maturities between 5 and 10 years. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the bonds that make up the Target Index.

Principal Risks

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.

Annual Total Returns — Vanguard Intermediate-Term Corporate Bond Index Fund ETF Shares

The highest and lowest returns for a calendar quarter during the periods shown in the bar chart and the year-to-date return as of the most recent calendar quarter were:

	Total Return	Quarter
Highest	9.65 %	June 30, 2020
Lowest	-6.96 %	March 31, 2022
Year-to-Date Return	8.10 %	September 30, 2025

Average Annual Total Returns for Periods Ended December 31, 2024

	1 Year	5 Years	10 Years
Vanguard Intermediate-Term Corporate Bond Index Fund ETF Shares
Based on NAV
Return Before Taxes	3.26 %	0.85 %	2.73 %
Return After Taxes on Distributions	1.43	-0.50	1.32
Return After Taxes on Distributions and Sale of Fund Shares	1.91	0.09	1.48
Based on Market Price
Return Before Taxes	3.20	0.79	2.69
Bloomberg U.S. 5-10 Year Corporate Bond Index (reflects no deduction for fees, expenses, or taxes)	3.21 %	0.89 %	2.82 %
Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	1.33	-0.27	1.39

Investment Advisor

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

Portfolio Managers

Joshua C. Barrickman, CFA, Principal of Vanguard and Portfolio Manager at VCM. He has managed the Fund since its inception in 2009 (co-managed since 2025).

Jake Riley, CFA, Portfolio Manager at VCM. He has co-managed the Fund since 2025.

Purchase and Sale of Fund Shares

the NAV of the shares. The brokerage firm may charge you a commission to execute the transaction. Unless imposed by your brokerage firm, there is no minimum dollar amount you must invest and no minimum number of shares you must buy. ETF Shares of the Fund cannot be directly purchased from or redeemed with the Fund, except by certain authorized broker-dealers. These broker-dealers may purchase and redeem ETF Shares only in large blocks known as creation units, typically in exchange for baskets of securities.

Tax Information

Payments to Financial Intermediaries

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

Vanguard Long-Term Corporate Bond ETF

Investment Objective

Vanguard Long-Term Corporate Bond ETF, an exchange-traded share class of Vanguard Long-Term Corporate Bond Index Fund (the “Fund”), seeks to track the performance of a market-weighted corporate bond index with a long-term dollar-weighted average maturity.

Fees and Expenses

Shareholder Fees
(Fees paid directly from your investment)


Transaction Fee on Purchases and Sales	None*
Transaction Fee on Reinvested Dividends	None*
Transaction Fee on Conversion to ETF Shares	None*

None through Vanguard (Broker fees vary)

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


Management Fees	0.03 %
12b-1 Distribution Fee	None
Other Expenses	0.00 %
Total Annual Fund Operating Expenses	0.03 %

Example

1 Year	3 Years	5 Years	10 Years
$3	$10	$17	$39

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Portfolio Turnover

Principal Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the Bloomberg U.S. 10+ Year Corporate Bond Index (the “Target Index”), which includes U.S. dollar-denominated, investment-grade, fixed-rate, taxable debt securities issued by U.S. and non-U.S. industrial, utility, and financial companies, all with maturities greater than 10 years. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the bonds that make up the Target Index.

Principal Risks

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.

Annual Total Returns — Vanguard Long-Term Corporate Bond Index Fund ETF Shares

The highest and lowest returns for a calendar quarter during the periods shown in the bar chart and the year-to-date return as of the most recent calendar quarter were:

	Total Return	Quarter
Highest	13.81 %	December 31, 2023
Lowest	-12.77 %	June 30, 2022
Year-to-Date Return	7.77 %	September 30, 2025

Average Annual Total Returns for Periods Ended December 31, 2024

	1 Year	5 Years	10 Years
Vanguard Long-Term Corporate Bond Index Fund ETF Shares
Based on NAV
Return Before Taxes	-1.87 %	-1.87 %	2.15 %
Return After Taxes on Distributions	-3.85	-3.49	0.39
Return After Taxes on Distributions and Sale of Fund Shares	-1.09	-2.03	0.90
Based on Market Price
Return Before Taxes	-1.90	-2.00	2.07
Bloomberg U.S. 10+ Year Corporate Bond Index (reflects no deduction for fees, expenses, or taxes)	-1.95 %	-1.84 %	2.20 %
Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	1.33	-0.27	1.39

Investment Advisor

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

Portfolio Managers

Joshua C. Barrickman, CFA, Principal of Vanguard and Portfolio Manager at VCM. He has managed the Fund since its inception in 2009 (co-managed since 2025).

Jake Riley, CFA, Portfolio Manager at VCM. He has co-managed the Fund since 2025.

Purchase and Sale of Fund Shares

Tax Information

Payments to Financial Intermediaries

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

Vanguard Mortgage-Backed Securities ETF

Investment Objective

Vanguard Mortgage-Backed Securities ETF, an exchange-traded share class of Vanguard Mortgage-Backed Securities Index Fund (the “Fund”), seeks to track the performance of a market-weighted mortgage-backed securities index.

Fees and Expenses

Shareholder Fees
(Fees paid directly from your investment)


Transaction Fee on Purchases and Sales	None*
Transaction Fee on Reinvested Dividends	None*
Transaction Fee on Conversion to ETF Shares	None*

None through Vanguard (Broker fees vary)

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


Management Fees	0.01 %
12b-1 Distribution Fee	None
Other Expenses	0.02 %
Total Annual Fund Operating Expenses	0.03 %

Example

1 Year	3 Years	5 Years	10 Years
$3	$10	$17	$39

This example does not include the brokerage commissions that you may pay to buy and sell ETF Shares of the Fund.

Portfolio Turnover

Principal Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the Bloomberg U.S. MBS Float Adjusted Index (the “Target Index”), which includes fixed-rate U.S. agency mortgage-backed pass-through securities issued by the Government National Mortgage Association (“Ginnie Mae” or “GNMA”), the Federal National Mortgage Association (“Fannie Mae” or “FNMA”), and the Federal Home Loan Mortgage Corporation (“Freddie Mac” or “FHLMC”). A mortgage-backed pass-through security is a fixed income structure that pools mortgage loans with similar characteristics into a mortgage-backed security. For purposes of constructing the Target Index, the index provider groups these pools into “pool aggregates” based on a variety of factors. To be included in the Target Index, pool aggregates must have at least $1 billion currently outstanding and a weighted average maturity of at least 1 year. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the bonds that make up the Target Index.

Principal Risks

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.

• Prepayment Risk. Certain bonds are subject to risks associated with prepayment. With respect to mortgage-backed, asset-backed, and similar debt securities, prepayment typically refers to borrowers repaying their debt early (e.g., before the maturity date). Prepayment of bonds held by the Fund would result in the Fund losing any price appreciation above the amount repaid. In addition, because prepayments occur more frequently in low

interest rate environments, the Fund likely would be forced to reinvest the proceeds from any prepayments at a lower interest rate than when the prepaid bonds were purchased, resulting in a decline in the Fund’s income and a potential loss in the value of the Fund’s investments. Frequent prepayments and subsequent reinvestment of the proceeds also would increase the Fund’s turnover rate.

• Extension Risk. During periods of rising interest rates, certain bonds held by the Fund may be paid off substantially more slowly than originally anticipated. As a result, the value of the bonds may fall, resulting in a decline in the Fund’s income and a potential loss in the value of the Fund’s investments.

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.

Annual Total Returns — Vanguard Mortgage-Backed Securities Index Fund ETF Shares

The highest and lowest returns for a calendar quarter during the periods shown in the bar chart and the year-to-date return as of the most recent calendar quarter were:

	Total Return	Quarter
Highest	7.34 %	December 31, 2023
Lowest	-5.17 %	September 30, 2022
Year-to-Date Return	6.76 %	September 30, 2025

Average Annual Total Returns for Periods Ended December 31, 2024

	1 Year	5 Years	10 Years
Vanguard Mortgage-Backed Securities Index Fund ETF Shares
Based on NAV
Return Before Taxes	1.43 %	-0.71 %	0.85 %
Return After Taxes on Distributions	-0.17	-1.72	-0.16
Return After Taxes on Distributions and Sale of Fund Shares	0.84	-0.95	0.22
Based on Market Price
Return Before Taxes	1.71	-0.67	0.87
Bloomberg U.S. MBS Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	1.54 %	-0.57 %	0.96 %
Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	1.33	-0.27	1.39

Investment Advisor

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

Portfolio Manager

Joshua C. Barrickman, CFA, Principal of Vanguard and Portfolio Manager at VCM. He has managed the Fund since 2013.

Purchase and Sale of Fund Shares

redeemed with the Fund, except by certain authorized broker-dealers. These broker-dealers may purchase and redeem ETF Shares only in large blocks known as creation units, typically in exchange for cash.

Tax Information

Payments to Financial Intermediaries

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

More on Principal Risks

General Market Risk. The markets in which the Funds invest 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 Funds’ investments, thereby resulting in potential losses to the Funds over short or long periods.

Investing in Bond Markets. Each Fund may be impacted by the general condition of the bond markets and by factors that affect bonds and bond issuers. For example, as a general rule, bond prices and interest rates move in opposite directions. When interest rates rise, bond prices tend to fall, and when interest rates fall, bond prices tend to go up. Bond income also is affected by changes in interest rates. Interest rates can rise or fall for a number of reasons,

including, but not limited to, central bank monetary policy, inflationary or deflationary pressures, and changes in general market and economic conditions. Changing interest rates, including, but not limited to, rates that fall below zero, could have unpredictable effects on the overall market and may expose the bond markets in particular to heightened volatility and potential illiquidity. The degree to which a Fund is impacted by the following bond market risks may vary based on factors disclosed throughout this Prospectus, such as the types of bonds in which it invests and the overall credit quality, average maturity, and/or average duration of its bond holdings.

Interest Rate Risk. A Fund’s investments in bonds can be sensitive to interest rate changes and may be affected differently depending on the overall interest rate environment. During periods of rising interest rates, bond prices overall may decline, which could result in a decline in a Fund’s value. The prices of longer-term bonds are more sensitive to changes in interest rates than the prices of shorter-term bonds.

Income Risk. During periods of falling interest rates, a Fund’s income may decline because a Fund may have to invest new cash flow and cash from maturing bonds in bonds with lower yields. The income paid by shorter-term bonds is subject to a higher degree of fluctuation than the income paid by longer-term bonds.

Credit Risk. Credit risk refers to the chance that an issuer will default (fail to meet its credit obligations) or fail to make payments in a timely manner, which could result in a loss to a Fund. In addition, negative perceptions of an issuer’s ability to make payments can cause the price of a security to decline. A Fund could be impacted by factors negatively impacting the issuers of its corporate bond holdings. For example, if a company is restructured, there could be a substantial decline in the credit quality and market value of any bonds issued by that company. While all debt securities are subject to credit risk to some extent, those with higher credit quality ratings generally pose less credit risk than those with lower credit quality ratings.

Bond Liquidity Risk. If a Fund is unable to sell a security at an advantageous time or price, its returns may be reduced. There may be limited trading in the secondary market for certain debt securities, which could make them more difficult to value or sell. For example, liquidity in the corporate bond market may be impacted by overall market conditions or by a decline in the availability of credit.

Call Risk (Applies to Vanguard Short-Term Corporate Bond Index Fund, Vanguard Intermediate-Term Corporate Bond Index Fund, Vanguard Long-Term Corporate Bond Index Fund, and Vanguard Mortgage-Backed Securities Index Fund). Certain bonds held by a Fund may be callable. The issuer of a callable

bond has the right to “call” (redeem) the bond before its maturity date. When a bond is called, the principal value of the bond is repaid earlier than anticipated (prepayment) and the investor (in this case, a Fund) no longer receives the interest payments that would have been paid up to the expected maturity date. In addition, bond calls and the resulting prepayments cause a Fund to lose any price appreciation that would have occurred between the time the bond was called and its original maturity date.

During periods of falling interest rates, it benefits issuers to call bonds with high interest rates. When this occurs, a Fund likely will be forced to reinvest the proceeds of any called bonds at a lower interest rate than that of the called bonds, resulting in a decline in the Fund’s income and a potential loss in the value of the Fund’s investments. If a Fund holds multiple callable bonds, frequent bond calls (as is likely during periods of falling interest rates) and the Fund’s subsequent reinvestment of the proceeds also would increase the Fund’s turnover rate.

Prepayment Risk (Applies to Vanguard Mortgage-Backed Securities Index Fund). Certain bonds may be repaid in full prior to their maturity dates. Prepayment can be driven by bond calls or by borrowers repaying their debt earlier than anticipated (in the case of mortgage-backed, asset-backed, and similar debt securities such as collateralized mortgage obligations). In both cases, prepayment results in the principal value of a bond being repaid prior to its maturity date, resulting in fewer interest payments overall. Prepayments cause the investor (in this case, the Fund) to lose any price appreciation that would have occurred between the time the principal was paid in full and the original maturity date.

Prepayments occur more frequently in low interest rate environments. For example, during periods of falling interest rates, homeowners are more likely to refinance their mortgages, resulting in prepayment of mortgage-backed securities. Similarly, credit card holders are more likely to pay off their credit card bills, resulting in prepayment of asset-backed securities. As an investor in these securities, the Fund likely would be forced to reinvest the proceeds from any prepayments at a lower interest rate than when the prepaid bonds were purchased, resulting in a decline in the Fund’s income and a potential loss in the value of the Fund’s investments. In addition, frequent prepayments (as is likely during periods of falling interest rates) and the Fund’s subsequent reinvestment of the proceeds would increase the Fund’s turnover rate.

Extension Risk (Applies to Vanguard Mortgage-Backed Securities Index Fund). During periods of rising interest rates, certain bonds held by the Fund may be paid off substantially more slowly than originally anticipated. As a result, the value of the bonds may fall, resulting in a decline in the Fund’s income and a potential loss in the value of the Fund’s investments. For example,

investments in mortgage-backed securities are subject to the risk that homeowners will repay their mortgages more slowly than anticipated during periods of rising interest rates, which would extend the duration of mortgage-backed securities held by the Fund. The proceeds from such securities would then be unavailable to reinvest at higher interest rates.

Index Investing. Each Fund is subject to the following risks associated with index investing: 

Passive Management. Each Fund seeks to track the performance of its Target Index regardless of how the Target Index is performing. The advisor’s use of an indexing, or passive, approach to select and maintain investments for each Fund means that the advisor will select investments for the purpose of tracking the Target Index and generally will not use strategies to reduce negative impacts to the Fund during periods of market volatility. As a result, a Fund’s performance may be lower than it would be if it were actively managed. 

Index Sampling Strategy. Because each Fund does not hold all of the securities included in its Target Index, each Fund is subject to the risk that the representative sample of securities selected by the advisor will, in the aggregate, vary from the investment profile of the full Target Index.

Tracking Error. The performance of a Fund’s investments, in the aggregate, may not match the investment performance of its Target Index. It is important to understand that an index fund will never perform exactly the same as its target index because, among other things, an index fund has operating expenses and transaction costs and its target index does not. Beyond these inherent differences in the operation of an index fund versus the operation of its target index, there are a variety of other factors that can cause or result in tracking error. These may include, but are not limited to: 

○

Price differences between the securities held by the index fund and those included in its target index 

○

Cash flows into or out of the index fund  

○

The size of the index fund

○

Compliance with new or existing regulatory requirements 

○

Portfolio transactions carried out by the index fund’s advisor to minimize the distribution of capital gains 

○

Changes to the underlying securities that make up the target index 

○

Errors made by the provider of the target index

Tracking error risk may be heightened during times of increased market volatility or under other unusual market conditions. An index fund using a sampling strategy may be more likely to experience tracking error than an index fund using a replicating strategy. 

Index Provider. Each Fund is subject to risks associated with its index provider. The securities that make up a Target Index and their weighting in the Target Index are determined by the index provider. The index provider does not provide any warranty or accept any liability with respect to the quality, accuracy, or completeness of the Target Index or any data used to compile the Target Index. Under normal circumstances, the index provider rebalances (updates) the Target Index on a regular schedule. However, the index provider may also rebalance the Target Index outside of the regular schedule or delay or cancel a scheduled rebalance, which could result in added costs for a Fund or cause a Fund to experience tracking error. The index provider may make errors, and it is possible that such errors may not be identified by the index provider for a period of time or at all. Any gains, losses, or costs associated with or resulting from an error made by the index provider will generally be borne by a Fund and, as a result, a Fund’s shareholders. A Fund’s advisor does not provide any warranty or guarantee against any errors made by the index provider.

ETF Share Trading. Because ETF Shares trade on the secondary markets, they are subject to the following risks:

ETF Shares Trading at Prices Other Than NAV. ETF Shares may trade on a national securities exchange at prices above, below, or at their most recent NAV. The NAV of a Fund’s ETF Shares, which typically is calculated at the end of each business day, will generally fluctuate with changes in the market value of the Fund’s holdings. The market prices of ETF Shares will also fluctuate, in some cases materially, in accordance with changes in NAV and the intraday value of a Fund’s holdings, as well as the relative supply of and demand for the ETF Shares on an exchange. Differences between secondary market prices of ETF Shares and the intraday value of a Fund’s holdings may be due largely to supply and demand forces in the secondary market, which may not be the same forces as those influencing prices for securities held by the Fund at a particular time.

Although it is expected that the market price of an ETF Share typically will trade close to the value of a Fund’s holdings, market prices are not expected to correlate exactly to a Fund’s NAV due to timing reasons, supply and demand imbalances, and other factors. In addition, disruptions to creations and redemptions; adverse developments impacting market makers, authorized participants, or other market participants; or high market volatility may result in the market price of ETF Shares differing significantly from a Fund’s NAV or the intraday value of a Fund’s holdings. As a result of these factors, among others,

you may pay more (premium) or less (discount) 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. These discounts and premiums are likely to be greatest during times of market disruption or extreme market volatility.

Cost of Buying or Selling Shares. Individual investors who buy or sell ETF Shares through a broker may incur a brokerage commission or other charges imposed by brokers. In addition, the market price of ETF Shares, like the price of any security on an exchange, includes a “bid-ask spread” charged by the market makers or other participants that trade the particular security. The bid-ask spread is the difference between the highest price a buyer is willing to pay to purchase ETF Shares (bid) and the lowest price a seller is willing to accept for ETF Shares (ask) when buying or selling shares in the secondary market. The bid-ask spread of a Fund’s ETF Shares can vary over time based on the Fund’s trading volume and market liquidity and may increase if the Fund’s trading volume, the bid-ask spread of the Fund’s underlying securities, or market liquidity decrease. In times of severe market disruption, including when trading of a Fund’s holdings may be halted, the bid-ask spread may increase significantly. This means that ETF Shares may trade at a discount to a Fund’s NAV, and the discount is likely to be greatest during significant market volatility.

Short Selling. ETF Shares, similar to shares of other issuers listed on an exchange, may be sold short. In a short sale, an investor “borrows” securities from a lender for a fee and then sells the borrowed securities on the open market with the hope that the borrowed securities decline in price before the investor has to repurchase the securities to return them to the lender. Short sales of ETF Shares can increase their volatility and lead to price decreases.

Lack of Active Trading Market. Although ETF Shares are listed on a national securities exchange, it is possible that an active trading market may not be maintained. Although this could happen at any time, it is more likely to occur during times of severe market disruption. If you attempt to sell your ETF Shares when an active trading market is not functioning, you may have to sell at a significant discount to NAV. In extreme cases, you may not be able to sell your shares at all.

Trading Halt. Trading of ETF Shares on an exchange may be halted by the activation of individual or market-wide trading halts (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of ETF Shares may also be halted if (1) the shares are delisted from the listing exchange without first being listed on another exchange or (2) exchange officials determine that such action

is appropriate in the interest of a fair and orderly market or for the protection of investors. If a trading halt or unanticipated early closing of an exchange occurs, a shareholder may be unable to purchase or sell ETF Shares.

Authorized Participants.  Only Authorized Participants may engage in creation or redemption transactions directly with each Fund. Each Fund has a limited number of financial institutions that may act as Authorized Participants. A Fund’s Authorized Participants are not obligated to engage in creation or redemption transactions. To the extent that a 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.

Additional Risks

Geopolitical and Sanctions Risk. Due to growing dependencies between global economies, geopolitical events can negatively affect all securities, markets, and economies. It is possible that events which only impact one geographic area could have negative short- or long-term effects on markets, issuers, and/or exchanges in the United States and other countries.

At times, the United States, other governments, or other supranational bodies (e.g., the United Nations) may impose sanctions on countries and/or entities in response to geopolitical events or other priorities. Compliance with sanctions could impact the Funds, including the Funds’ abilities to transact in or obtain exposure to certain foreign securities and assets. Sanctions also could cause significant losses to the Funds’ investments and its performance could be negatively impacted. In lieu of sanctions, companies or specific goods that the company produces could be subjected to trade embargoes or tariffs, which can also affect securities markets and create volatility. So long as sanctions do not prohibit investment in the company or issuer, the Funds typically also would not be prohibited from investing in the affected company or issuer.

ETF Share Class Risks. By investing in the ETF Shares of a fund that also offers conventional mutual fund shares, you could be subject to costs and/or tax impacts that you would not be subject to if you invested in exchange-traded shares offered by a fund without a conventional mutual fund share class. These costs include brokerage and other transaction costs associated with a Fund buying and selling portfolio securities in response to conventional mutual fund share class inflows and outflows, cash drag as a result of a Fund holding the cash necessary to satisfy conventional mutual fund share class transactions, and taxable capital gains distributions if a Fund has to sell portfolio holdings at a gain in order to satisfy mutual fund share class redemptions.

Potential Redemption Activity Impacts. The Vanguard funds can be negatively impacted by certain large redemptions. These redemptions could occur due to a single shareholder or multiple shareholders deciding to sell a large quantity of shares of a fund or a share class of the fund. Large redemptions can occur for many reasons, either as a result of actions taken by the Vanguard funds or their advisors, or as a result of events unrelated to actions taken by the Vanguard funds or their advisors. Actions taken by the Vanguard funds or their advisors could include, but are not limited to, changes to a fund’s advisor(s), changes to a fund’s portfolio manager(s), changes to the composition of a fund’s portfolio, and/or other product changes or launches that, for example, result in shareholders redeeming shares of one fund to purchase shares of another fund or investment vehicle. For a fund of funds, actions taken by the Vanguard funds or their advisors could include a withdrawal from an underlying fund or a change in the allocation to underlying funds. Events unrelated to actions taken by the Vanguard funds or their advisors could include shareholders selling out of a fund in response to market movements or regulatory changes.

A large redemption could adversely affect a fund’s liquidity and NAV. For example, a large redemption could require a fund’s manager to sell portfolio holdings at unplanned or inopportune times. The manager’s sale of these holdings, which is a taxable event, could require the fund to distribute any corresponding capital gains or other taxable income to the fund’s remaining shareholders; see Dividends, Distributions, and Taxes in the Investing in Vanguard ETF® Shares section for additional information. The increased trading activity could also increase underlying costs for the fund due to commissions paid by the fund.

Investing in Derivatives. Investing in derivatives may present risks different from, and/or greater than, those associated with investing directly in stocks, bonds, or other types of investments. Derivatives could expose a Fund to increased volatility and/or significant loss. Certain derivatives have an inherent leverage component, providing the Fund exposure to a sizable position in an underlying asset with a relatively small upfront investment at the time the Fund enters into the derivatives position. For these derivatives, an adverse change in the value or price of the underlying asset could result in a loss substantially greater than the amount invested in the derivative itself. Some derivatives require the Fund to enter into a contract with a counterparty. If the counterparty is unable or unwilling to fulfill its contractual obligation, the Fund may experience a loss. A liquid market may not always exist for the Fund’s derivatives positions. The Fund may be unable to sell or otherwise exit its derivatives position at desired times or prices, which could also result in a loss to the Fund. Some derivatives, particularly OTC derivatives, can be complex and often are valued subjectively. Valuation may be more difficult in times of market turmoil since many investors and market makers may be reluctant to

purchase complex instruments or quote prices for them. Improper valuations can result in increased cash payment requirements to counterparties or a loss of value to the Fund.

Derivatives may not perform as intended, which may result in losses to the Fund. For example, derivatives used for hedging or as a substitute for a portfolio instrument may not provide the expected benefits, particularly during adverse market conditions. The use of derivatives is also subject to legal risk, which includes the risk of loss resulting from insufficient or unenforceable contractual documentation, insufficient capacity or authority of the Fund’s counterparty, and operational risk, which includes documentation or settlement issues, system failures, inadequate controls, and human error.

Other Investment Policies

In addition to employing its principal investment strategies, each Fund may use the following other investment strategies and types of investments in order to achieve its investment objective.

Substitute Index

Each Fund reserves the right to substitute a different index for the index it currently tracks if a current index is discontinued, if the Fund’s agreement with the provider of its Target index is terminated, or for any other reason determined in good faith by the Board. In any such instance, a substitute index would represent the same market segment as the Target index.

Other Types of Investments

Up to 20% of each Fund’s assets may be used to purchase 144A securities, which are nonpublic, investment-grade securities exempt from registration requirements under Rule 144A of the Securities Act of 1933, as well as smaller public issues or medium-term notes not included in a Fund’s Target Index because of the small size of the issue. The vast majority of such securities will have characteristics and risks similar to the bonds included in a Fund’s Target Index. Subject to the same 20% limit, each Fund may also purchase other investments that are not included in its Target Index (such as those described below) or may hold bonds that were included in the Target Index when acquired but subsequently have been removed.

Vanguard Mortgage-Backed Securities Index Fund may enter into transactions involving mortgage-backed securities, such as To Be Announced (“TBA”) transactions or mortgage dollar rolls. The Fund may enter TBA transactions as a buyer or a seller. When entering into TBA transactions as a seller, the Fund may sell a TBA mortgage-backed security that it does not hold (i.e., engage in a short sale. The Fund will use mortgage dollar rolls only if their use is consistent with the Fund’s investment objective and principal investment strategies. A

description of each of these investments is provided below.

Each Fund may invest in cash equivalent investments, which is a blanket term that describes a variety of short-term fixed income investments, including money market instruments, commercial paper, bank certificates of deposit, banker’s acceptances, and repurchase agreements. Repurchase agreements represent short-term (normally overnight) loans by a fund to banks or large securities dealers. Vanguard Short-Term Treasury Index Fund, Vanguard Intermediate-Term Treasury Index Fund, Vanguard Long-Term Treasury Index Fund, and Vanguard Mortgage-Backed Securities Index Fund may invest only in repurchase agreements that are collateralized by U.S. Treasury or U.S. government agency securities. The Funds’ advisor believes that risks associated with repurchase agreements can be controlled through careful security selection and monitoring.

Each Fund may invest in derivatives. In general, a derivative is a financial contract whose value is based on the value of a financial asset (such as a stock, a bond, or a currency), a physical asset (such as gold, oil, or wheat), a market index, or a reference rate. Each Fund may invest in derivatives only if the expected risks and rewards of the derivatives are consistent with the investment objective, policies, strategies, and risks of the Fund as disclosed in this Prospectus. In particular, derivatives will be used only when they may help the advisor to accomplish one or more of the following:

• Invest in eligible asset classes with greater efficiency and lower cost than is possible through direct investment.

• Add value when these instruments are favorably priced.

• Adjust sensitivity to changes in interest rates.

• Adjust overall credit risk of the portfolio.

The Funds’ derivative investments may include fixed income futures contracts, fixed income options, interest rate swaps, total return swaps, credit default swaps, or other derivatives.

Each Fund may invest a small portion of its assets in shares of exchange-traded funds (ETFs), which typically provide returns similar to those of bonds. Each Fund may purchase ETFs when doing so will reduce the Fund’s transaction costs, facilitate cash management, mitigate risk, or have the potential to add value because the instruments are favorably priced. Vanguard receives no additional revenue from Fund assets invested in ETF shares of other Vanguard funds. Fund assets invested in ETF shares of other Vanguard funds are excluded when allocating to the Fund its share of the costs of Vanguard’s operations.

Cash Management

Each Fund’s daily cash balance may be invested in one or more Vanguard CMT Funds, which are used as cash management vehicles for the Vanguard funds. When investing in a CMT Fund, each Fund bears its proportionate share of the expenses of the CMT Fund in which it invests. Vanguard receives no additional revenue from Fund assets invested in a CMT Fund.

Temporary Defensive Measures

Each Fund may temporarily depart from its normal investment policies and strategies when the advisor believes that doing so is in the Fund’s best interest, so long as the strategy or policy employed is consistent with the Fund’s investment objective. For instance, a Fund may invest beyond its normal limits in derivatives or exchange-traded funds that are consistent with the Fund’s investment objective when those instruments are favorably priced or provide needed liquidity, as might be the case when the Fund receives large cash flows that it cannot prudently invest immediately.

Portfolio Holdings

Please consult the Funds' Statement of Additional Information or Vanguard’s website for a description of the policies and procedures that govern disclosure of each Fund’s portfolio holdings.

Management and Distribution of the Funds

Each Fund is a member of The Vanguard Group, Inc. (Vanguard), a family of over 200 funds. All of the funds that are members of Vanguard (other than funds of funds) share in the expenses associated with administrative services and business operations, such as personnel, office space, and equipment.

Vanguard Marketing Corporation provides marketing services to the funds. Although fund shareholders do not pay sales commissions or 12b-1 distribution fees, each fund (other than a fund of funds) or each share class of a fund (in the case of a fund with multiple share classes) pays its allocated share of the Vanguard funds’ marketing costs.

How is Vanguard’s Corporate Structure Unique?

Vanguard is owned jointly by the funds it oversees and thus indirectly by

the shareholders in those funds. Most other mutual funds are operated by

management companies that are owned by third parties—either public or

private stockholders—and not by the funds they serve.

Investment Advisor

The Vanguard Group, Inc., P.O. Box 2600, Valley Forge, PA 19482, which began operations in 1975, serves as advisor to the Funds through Vanguard Capital Management (VCM). VCM exercises portfolio management responsibilities for the Funds. As of August 31, 2025, Vanguard served as advisor for approximately $9.3 trillion in assets. Vanguard, through VCM, provides investment advisory services to the Funds pursuant to the Funds’ Service Agreement and an intercompany service agreement between Vanguard and VCM, subject to the supervision and oversight of the trustees and officers of the Funds.

VCM, P.O. Box 2600, Valley Forge, PA 19482, is a wholly owned subsidiary of Vanguard and was established in 2025.

For the fiscal year ended August 31, 2025, the advisory expenses for each Fund represented an effective annual rate of less than 0.01% of the Fund’s average net assets.

Each Fund reserves the right to utilize a multimanager approach in the future. Under the terms of an SEC exemption, the Board may, without prior approval from shareholders, change the terms of an advisory agreement with a third-party investment advisor or hire a new third-party investment advisor—either as a replacement for an existing advisor or as an additional advisor. Any significant change in a Fund’s advisory arrangement will be communicated to shareholders in writing. As Vanguard is the Funds’ sponsor and overall manager, Vanguard, through VCM, may provide investment advisory services to a Fund under certain circumstances. Vanguard may also recommend to the Board that an advisor be hired, terminated, or replaced or that the terms of an existing advisory agreement be revised. The Funds have filed an application seeking an SEC exemption with respect to investment advisors that are wholly owned subsidiaries of Vanguard. If the exemption is granted, the Funds may rely on the new SEC relief.

A discussion regarding the basis for the Board’s approval of each Fund’s investment advisory arrangement is available in the Fund’s Form N-CSR filed with the SEC for the fiscal year ended August 31 and in the applicable Financial Statements and Other Information document available on the Fund’s website.

The managers primarily responsible for the day-to-day management of the Funds are:

Joshua C. Barrickman, CFA, Principal of Vanguard, Portfolio Manager at VCM, and co-head of Vanguard’s Fixed Income Indexing Americas. He has been with Vanguard since 1998; has worked in investment management since 1999; has managed investment portfolios since 2005; has managed Vanguard Short-Term Corporate Bond Index Fund, Vanguard Intermediate-Term Corporate Bond Index Fund, and Vanguard Long-Term Corporate Bond Index

Fund since their inceptions in 2009 (co-managed since 2025); and has managed Vanguard Short-Term Treasury Index Fund, Vanguard Intermediate-Term Treasury Index Fund, Vanguard Long-Term Treasury Index Fund and Vanguard Mortgage-Backed Securities Index Fund since 2013. Education: B.S., Ohio Northern University; M.B.A., Lehigh University.

Jake Riley, CFA, Portfolio Manager at VCM. He has been with Vanguard since 2008; has worked in investment management since 2011; and has co-managed Vanguard Short-Term Corporate Bond Index Fund, Vanguard Intermediate-Term Corporate Bond Index Fund, and Vanguard Long-Term Corporate Bond Index Fund since 2025. Education: B.S., James Madison University; M.B.A., University of Chicago Booth School of Business.

The Funds' Statement of Additional Information provides information about each portfolio manager’s compensation, other accounts under management, and ownership of shares of the Funds.

Investing in Vanguard ETF® Shares

Each Vanguard fund may offer one or more share classes. If a Vanguard fund offers multiple share classes, each share class has the same investment objective, strategies, and policies. However, because different share classes can have different expenses, their investment returns may differ. Vanguard and the Funds have received an exemptive order from the SEC that permits the Funds to offer conventional mutual fund shares and ETF shares. This Prospectus offers the Funds’ ETF shares.

The Funds’ ETF Shares are listed for trading on Nasdaq. You can buy and sell ETF Shares on the secondary market in the same way you buy and sell any other exchange-traded security—through a broker. Your broker may charge a commission to execute a transaction. Unless imposed by your broker, there is no minimum dollar amount you must invest and no minimum number of ETF Shares you must buy.

Your ownership of ETF Shares will be shown on the records of the broker through which you hold the shares. Vanguard will not have any record of your ownership. Your account information will be maintained by your broker, which will provide you with account statements, confirmations of your purchases and sales of ETF Shares, and tax information. Your broker also will be responsible for ensuring that you receive income and capital gains distributions, as well as shareholder reports and other communications from the fund whose ETF Shares you own. You will receive other services (e.g., dividend reinvestment and average cost information) only if your broker offers these services.

Redemption of ETF Shares by Authorized Participants

Unlike conventional (i.e., not exchange-traded) mutual fund shares, ETF Shares cannot be purchased directly from or redeemed directly with the issuing fund by an individual investor. Instead, only Authorized Participants can purchase and redeem ETF Shares directly from the issuing fund. Authorized Participants may purchase and redeem ETF Shares from the issuing fund only in large blocks (creation units), usually in exchange for baskets of securities. Funds may also issue and redeem creation units in exchange for solely cash or a combination of cash and securities. These trades may occur in-kind between Vanguard and the Authorized Participant. If cash is used to meet redemptions, a Fund typically obtains such cash through positive cash flows or the sale of Fund holdings consistent with the Fund’s investment objective and strategy.

Under certain circumstances, including under stressed market conditions, a Fund may borrow money (subject to certain regulatory conditions and if available under board-approved procedures) through an interfund lending

facility; through a bank line-of-credit, including a joint committed credit facility; or through an uncommitted line-of-credit from Vanguard in order to meet redemption requests.

Conversion Privilege

Owners of conventional shares issued by a Fund may convert those shares to ETF Shares of equivalent value of the same fund. Please note that investors who own conventional shares through a 401(k) plan or other employer-sponsored retirement or benefit plan generally may not convert those shares to ETF Shares and should check with their plan sponsor or recordkeeper. ETF Shares, whether acquired through a conversion or purchased on the secondary market, cannot be converted to conventional shares by a shareholder. Also, ETF Shares of one fund cannot be exchanged for ETF Shares of another fund.

ETF Shares must be held in a brokerage account. Thus, before converting conventional shares to ETF Shares, you must have an existing, or open a new, brokerage account. This account may be with Vanguard Brokerage Services® or with any other brokerage firm. To initiate a conversion of conventional shares to ETF Shares, please contact your broker.

Vanguard Brokerage Services does not impose a fee on conversions from Vanguard conventional shares to Vanguard ETF Shares. However, other brokerage firms may charge a fee to process a conversion. Vanguard reserves the right, in the future, to impose a transaction fee on conversions or to limit, temporarily suspend, or terminate the conversion privilege.

Converting conventional shares to ETF Shares is generally accomplished as follows. First, after your broker notifies Vanguard of your request to convert, Vanguard will transfer your conventional shares from your account to the broker’s omnibus account with Vanguard (an account maintained by the broker on behalf of all its customers who hold conventional Vanguard fund shares through the broker). After the transfer, Vanguard’s records will reflect your broker, not you, as the owner of the shares. Next, your broker will instruct Vanguard to convert the appropriate number or dollar amount of conventional shares in its omnibus account to ETF Shares of equivalent value, based on the respective NAVs of the two share classes.

Your Fund’s transfer agent will reflect ownership of all ETF Shares in the name of the Depository Trust Company (DTC). The DTC will keep track of which ETF Shares belong to your broker, and your broker, in turn, will keep track of which ETF Shares belong to you.

Because the DTC is unable to handle fractional shares, only whole shares can be converted. For example, if you owned 300.25 conventional shares, and this was equivalent in value to 90.75 ETF Shares, the DTC account would receive 90 ETF Shares. Conventional shares with a value equal to 0.75 ETF Shares (in

this example, that would be 2.481 conventional shares) would remain in the broker’s omnibus account with Vanguard. Your broker then could either (1) credit your account with 0.75 ETF Shares or (2) redeem the 2.481 conventional shares for cash at NAV and deliver that cash to your account. If your broker chose to redeem your conventional shares, you would realize a gain or loss on the redemption that must be reported on your tax return (unless you hold the shares in an IRA or other tax-deferred account). Please consult your broker for information on how it will handle the conversion process, including whether it will impose a fee to process a conversion.

If you convert your conventional shares to ETF Shares through Vanguard Brokerage Services, all conventional shares for which you request conversion will be converted to ETF Shares of equivalent value. Because no fractional shares will have to be sold, the transaction will not be taxable.

Here are some important points to keep in mind when converting conventional shares of a Vanguard fund to ETF Shares:

• The conversion process can take anywhere from several days to several weeks, depending on your broker. Vanguard generally will process conversion requests either on the day they are received or on the next business day. Vanguard imposes conversion blackout windows around the dates when a fund with ETF Shares declares dividends. This is necessary to prevent a shareholder from collecting a dividend from both the conventional share class currently held and also from the ETF share class to which the shares will be converted.

• Until the conversion process is complete, you will remain fully invested in a fund’s conventional shares, and your investment will increase or decrease in value in tandem with the NAV of those shares.

• The conversion transaction is nontaxable except, if applicable, to the very limited extent previously described.

Pricing of Fund Shares

ETF Shares may only be bought and sold in the secondary market. The price you pay or receive for the ETF Shares will be the prevailing market price, which may be more or less than the Fund’s NAV. Your transaction will be priced at the NAV only if you purchase or redeem your ETF Shares in creation unit blocks (an option available only to certain authorized broker-dealers), or if you convert your conventional fund shares to ETF Shares. NAV is typically calculated as of the close of regular trading on the New York Stock Exchange (“NYSE”), generally 4 p.m., Eastern time, on each day that the NYSE is open for business (a business day). In the rare event the NYSE experiences unanticipated disruptions and is unavailable at the close of the trading day, NAVs will be calculated as of the close of regular trading on the Nasdaq (or another alternate exchange if the Nasdaq is unavailable, as determined at Vanguard’s discretion),

generally 4 p.m., Eastern time. The time selected for NAV calculation in this rare event generally shall also serve as the conclusion of the trading day. On U.S. holidays or other days when the NYSE is closed, the NAV is not calculated, and the Vanguard funds do not sell or redeem shares. However, on those days the value of a fund’s assets may be affected to the extent that the fund holds securities that change in value on those days (such as foreign securities that trade on foreign markets that are open).

If a fund only has one share class, the NAV per share is computed by dividing the total assets, minus liabilities, of a fund by the number of fund shares outstanding. If a fund has more than one share class, each share class has its own NAV, which is computed by dividing the total assets, minus liabilities, allocated to the share class by the number of fund shares outstanding for that class. The value of securities and other investments held by the Vanguard funds is determined pursuant to the valuation policies and procedures adopted by the Vanguard funds’ boards of trustees. Vanguard has been designated as the valuation designee for the Vanguard funds pursuant to Rule 2a-5 under the Investment Company Act of 1940, subject to oversight by the Vanguard funds’ boards of trustees.

Securities for which market quotations are readily available are valued at their market value, based on quotations provided by independent third-party pricing sources. Such securities are generally valued at their official closing price, the last reported sales price, or if there were no sales that day, the mean between the closing bid and asking prices, from the principal exchange or market on which they are traded. A fund’s investments in any mutual fund shares, including institutional money market fund shares, are valued at the NAVs of the mutual fund shares. A fund’s investments in any ETF shares or closed-end fund shares are valued at the market value of those shares.

When the market quotations are not readily available or do not accurately reflect the value of a security or other investment, such security or other investment is priced at fair value, generally based on information provided by independent third-party pricing services, in accordance with the valuation policies and procedures adopted by the Vanguard funds’ boards of trustees. Fair value represents a good faith determination of the value of a fund’s investments. The fair value of a security or other investment is the amount that the owner might reasonably expect to receive upon the current sale of the security or other investment. Fair-value pricing may require subjective determinations. It is possible that the price determined through fair-value pricing may differ from the price quoted or published by other sources and may not be the price at which those investments could have been sold during the period in which the fair value was used.

Fair-value pricing may be used in a variety of circumstances. For example, it may be used if the value of a security or other investment has been materially affected by events occurring after the close of the principal exchange or market

on which the security is traded but before the funds’ NAV is calculated. These events might be company-specific (e.g., earnings report, merger announcement), country-specific (e.g., significant price movements in U.S. or a foreign market), or regional/global events (e.g., natural disaster, economic or political news, interest rate change, act of terrorism). These events could affect a single security or a large number of securities in a particular market, and it most commonly occurs with foreign portfolio holdings because many foreign markets operate at times that do not coincide with those of the major U.S. markets. Events that could affect the value of the foreign portfolio holdings may occur between the close of the foreign market and the time a fund’s NAV is calculated. The values of any foreign securities held by a fund are converted into U.S. dollars using an exchange rate obtained from an independent third party as of the close of regular trading on the NYSE.

In addition, fair-value pricing may be used if trading in a security is halted and does not resume before a fund’s pricing time, a security does not trade in the course of a day and a fund holds enough of the security that its price could affect the NAV, or if the trading market on which a security is listed is suspended or closed and no appropriate alternative trading market is available.

Fixed income securities are generally valued based on information furnished by independent pricing services and are priced at fair value. Pricing services may use matrix pricing or valuation models that utilize certain inputs and assumptions to derive values. Pricing services generally value fixed income securities assuming orderly transactions of an institutional round lot size, but a fund may hold or transact in such securities in smaller odd lot sizes. Odd lots may trade at lower prices than institutional round lots.

Failures by third-party pricing services to carry out their obligations to the Vanguard funds (e.g., any errors in the data provided by third-party pricing services) could result in delays in the calculation of the funds’ NAVs and/or the inability to calculate the NAVs over extended time periods. The funds may be unable to recover any losses associated with such failures.

The Vanguard funds have authorized certain financial intermediaries and their designees, and may, from time to time, authorize certain funds of funds for which Vanguard serves as the investment advisor (Vanguard Funds of Funds), to accept orders to purchase or redeem fund shares on behalf of the Vanguard funds. In these circumstances, the Vanguard fund will be deemed to receive an order when accepted by the authorized financial intermediary, its designee, or one of the Vanguard Funds of Funds, and the order will be executed using the NAV next calculated after such acceptance.

Vanguard’s website will show the previous day’s closing NAV and closing market price for a fund’s ETF Shares. The website also discloses, in the Premium/Discount analysis section of a fund’s Price & Performance page, how frequently the fund traded at a premium or discount to NAV (based on closing NAVs and market prices) and the magnitudes of such premiums and discounts.

Dividends, Distributions, and Taxes

Fund Distributions

Each Fund generally distributes to shareholders virtually all of its net income (interest less expenses) as well as any net short-term or long-term capital gains realized from the sale of its holdings. Each Fund may also make distributions that are treated as a return of capital. Income dividends generally are declared and distributed monthly; capital gains distributions, if any, generally occur annually in December. In addition, each Fund may make a supplemental distribution at some other time during the year.

From time to time, Vanguard and/or a fund’s board of trustees may adjust a fund’s fees and expenses and/or reduce, refund, reimburse, waive, or otherwise return to the funds and their shareholders a portion of prior fees and expenses (collectively, “expense adjustments”). Fund performance and potentially shareholder distributions, will reflect such expense adjustments. If you sell all or part of your investment in a fund before an expense adjustment occurs, then you will not receive the economic benefit, if any, of such expense adjustment. An expense adjustment at any given time does not imply or guarantee that similar or additional expense adjustments will be made in the future.

Reinvestment of Distributions

In order to reinvest dividend and capital gains distributions, investors in a Fund’s ETF Shares must hold their shares at a broker that offers a reinvestment service. This can be the broker’s own service or a service made available by a third party, such as the broker’s outside clearing firm or the Depository Trust Company (DTC). If a reinvestment service is available, distributions of income and capital gains can automatically be reinvested in additional whole and fractional ETF Shares of a Fund. If a reinvestment service is not available, investors will receive their distributions in cash. To determine whether a reinvestment service is available and whether there is a commission or other charge for using this service, consult your broker.

Mutual fund share class holders will receive dividend payments before holders of ETF Shares. As with all exchange-traded funds, reinvestment of dividend and capital gains distributions in additional ETF Shares will occur two business days or more after the ex-dividend date (the date when a distribution of dividends or capital gains is deducted from the price of a Fund’s shares). The exact number

of days depends on your broker. During that time, the amount of your distribution will not be invested in a Fund and therefore will not share in the Fund’s income, gains, and losses.

Basic Tax Points

Investors in taxable accounts should be aware of the following basic federal income tax points:

• Distributions are taxable to you whether or not you reinvest these amounts in additional Fund shares.

• Distributions declared and recorded in December—if paid to you by the end of January—are generally taxable as if received in December.

• Any income dividend distribution or short-term capital gains distribution that you receive is taxable to you as ordinary income.

• Any distribution of net long-term capital gains is taxable to you as long-term capital gains, no matter how long you have owned shares in a Fund.

• Capital gains distributions can occur when a Fund sells assets at a gain. Capital gains distributions vary from year to year as a result of the Fund’s investment activities and cash flows, including those due to redemption activity by Fund shareholders.

• Capital gains distributions may occur if Vanguard, a Fund, or its advisor makes changes that would impact the Fund directly or indirectly, including changes to the Fund’s portfolio or advisors or changes to any other Vanguard fund or product that would involve the redemption of shares of the Fund and the related sale of the Fund’s investments. Such changes could, depending on the timing, result in capital gains distributions in the current fiscal year, subsequent fiscal year, or both.

• Your cost basis in the Fund will be decreased by the amount of any return of capital that you receive. This, in turn, will affect the amount of any capital gain or loss that you realize when selling your Fund shares.

• Return of capital distributions generally are not taxable to you until your cost basis has been reduced to zero. If your cost basis is at zero, return of capital distributions will be treated as capital gains.

• A sale of Fund shares is a taxable event. This means that you may have a capital gain to report as income, or a capital loss to report as a deduction, when you complete your tax return.

• If you purchase shares before an ex-dividend date when a fund has realized but not yet distributed income or capital gains, the purchase price may include the amount of the upcoming distribution, and you may pay the full price for the shares and later receive a portion of the purchase price back as a taxable distribution. In such case, you generally will be taxed upon receipt of such distribution, even though the distribution effectively represents a return of a portion of your purchase price. This is known as “buying a dividend.”

Individuals, trusts, and estates whose income exceeds certain threshold amounts are subject to a 3.8% Medicare contribution tax on “net investment income.” Net investment income takes into account distributions paid by the Fund and capital gains from any sale of Fund shares.

Income dividends and capital gains distributions that you receive, as well as your gains or losses from any sale of Fund shares, may be subject to state and local income taxes. Depending on your state’s rules, however, any dividends attributable to interest earned on direct obligations of the U.S. government may be exempt from state and local taxes. Vanguard will notify you each year how much, if any, of your dividends may qualify for this exemption.

This Prospectus provides general tax information only. 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. Please consult your own tax advisor for detailed information about any tax consequences for you.

Frequent Trading Limitations

Unlike frequent trading of a Vanguard fund’s conventional share classes, frequent trading of ETF Shares generally does not disrupt portfolio management or otherwise harm fund shareholders. The vast majority of trading in ETF Shares occurs on the secondary market. Because these trades do not involve the issuing fund, they do not pose potential harm to the fund or its shareholders. Certain broker-dealers are authorized to purchase and redeem ETF Shares directly with the issuing fund. Because these trades typically are effected in kind (i.e., for securities and not for cash), or are assessed a transaction fee when effected in cash, they do not cause any of the harmful effects to the issuing fund (as previously noted) that may result from frequent trading. For these reasons, the boards of trustees of Vanguard funds that issue ETF Shares have determined that it is not necessary to adopt policies and procedures to detect and deter frequent trading and market-timing of ETF Shares.

Financial Highlights

Financial highlights information is intended to help you understand a fund’s performance for the past five years (or, if shorter, its period of operations). Certain information reflects financial results for a single fund share. Total return represents the rate that an investor would have earned or lost each period on an investment in a fund or share class (assuming reinvestment of all distributions). This information has been obtained from the financial statements audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, whose report, along with fund financial statements, is included in a fund’s most recent annual Financial Statements and Other Information. You may obtain a free copy of a fund’s latest disclosure documents upon request.

Vanguard Short-Term Treasury Index Fund ETF Shares

For a Share Outstanding Throughout Each Period	Year Ended August 31,
For a Share Outstanding Throughout Each Period	2025	2024	2023	2022	2021
Net Asset Value, Beginning of Period	$58.76	$57.77	$58.51	$61.50	$62.13
Investment Operations
Net Investment Income1	2.418	2.343	1.625	.368	.288
Net Realized and Unrealized Gain (Loss) on Investments	.098	.973	(.919)	(2.860)	(.220)
Total from Investment Operations	2.516	3.316	.706	(2.492)	.068
Distributions
Dividends from Net Investment Income	(2.426)	(2.326)	(1.446)	(.310)	(.325)
Distributions from Realized Capital Gains	—	—	—	(.188)	(.373)
Total Distributions	(2.426)	(2.326)	(1.446)	(.498)	(.698)
Net Asset Value, End of Period	$58.85	$58.76	$57.77	$58.51	$61.50
Total Return	4.39%	5.88%	1.23%	-4.07%	0.11%
Ratios/Supplemental Data
Net Assets, End of Period (Millions)	$22,791	$20,022	$22,488	$15,565	$13,394
Ratio of Total Expenses to Average Net Assets	0.03%	0.04%	0.04%2	0.04%2	0.04%
Ratio of Net Investment Income to Average Net Assets	4.13%	4.04%	2.81%	0.61%	0.47%
Portfolio Turnover Rate3	93%	89%	81%	59%	66%

1	Calculated based on average shares outstanding.
2	The ratio of expenses to average net assets for the period net of reduction from custody fee offset arrangements was 0.04%.
3	Excludes the value of portfolio securities received or delivered as a result of in-kind purchases or redemptions of the fund’s capital shares, including ETF Creation Units.

Vanguard Intermediate-Term Treasury Index Fund ETF Shares

For a Share Outstanding Throughout Each Period	Year Ended August 31,
For a Share Outstanding Throughout Each Period	2025	2024	2023	2022	2021
Net Asset Value, Beginning of Period	$59.93	$58.20	$60.34	$68.27	$70.46
Investment Operations
Net Investment Income1	2.257	2.071	1.473	.858	.809
Net Realized and Unrealized Gain (Loss) on Investments	.108	1.615	(2.221)	(7.617)	(1.692)
Total from Investment Operations	2.365	3.686	(.748)	(6.759)	(.883)
Distributions
Dividends from Net Investment Income	(2.245)	(1.956)	(1.392)	(.805)	(.820)
Distributions from Realized Capital Gains	—	—	—	(.366)	(.487)
Total Distributions	(2.245)	(1.956)	(1.392)	(1.171)	(1.307)
Net Asset Value, End of Period	$60.05	$59.93	$58.20	$60.34	$68.27
Total Return	4.07%	6.49%	-1.25%	-10.01%	-1.26%
Ratios/Supplemental Data
Net Assets, End of Period (Millions)	$33,003	$30,317	$16,995	$11,726	$8,147
Ratio of Total Expenses to Average Net Assets	0.03%	0.04%	0.04%2	0.04%2	0.04%
Ratio of Net Investment Income to Average Net Assets	3.82%	3.55%	2.50%	1.34%	1.18%
Portfolio Turnover Rate3	55%	52%	36%	36%	33%

1	Calculated based on average shares outstanding.
2	The ratio of expenses to average net assets for the period net of reduction from custody fee offset arrangements was 0.04%.
3	Excludes the value of portfolio securities received or delivered as a result of in-kind purchases or redemptions of the fund’s capital shares, including ETF Creation Units.

Vanguard Long-Term Treasury Index Fund ETF Shares

For a Share Outstanding Throughout Each Period	Year Ended August 31,
For a Share Outstanding Throughout Each Period	2025	2024	2023	2022	2021
Net Asset Value, Beginning of Period	$60.50	$59.98	$68.45	$90.37	$98.93
Investment Operations
Net Investment Income1	2.450	2.348	2.008	1.718	1.645
Net Realized and Unrealized Gain (Loss) on Investments	(5.150)	.434	(8.567)	(21.974)	(8.289)
Total from Investment Operations	(2.700)	2.782	(6.559)	(20.256)	(6.644)
Distributions
Dividends from Net Investment Income	(2.470)	(2.262)	(1.911)	(1.664)	(1.625)
Distributions from Realized Capital Gains	—	—	—	—	(.291)
Total Distributions	(2.470)	(2.262)	(1.911)	(1.664)	(1.916)
Net Asset Value, End of Period	$55.33	$60.50	$59.98	$68.45	$90.37
Total Return	-4.52%	4.89%	-9.70%	-22.69%	-6.73%
Ratios/Supplemental Data
Net Assets, End of Period (Millions)	$9,832	$14,243	$7,322	$3,813	$2,366
Ratio of Total Expenses to Average Net Assets	0.03%	0.04%	0.04%2	0.04%2	0.04%
Ratio of Net Investment Income to Average Net Assets	4.30%	4.04%	3.19%	2.19%	1.81%
Portfolio Turnover Rate3	20%	21%	20%	19%	22%

1	Calculated based on average shares outstanding.
2	The ratio of expenses to average net assets for the period net of reduction from custody fee offset arrangements was 0.04%.
3	Excludes the value of portfolio securities received or delivered as a result of in-kind purchases or redemptions of the fund’s capital shares, including ETF Creation Units.

Vanguard Short-Term Corporate Bond Index Fund ETF Shares

For a Share Outstanding Throughout Each Period	Year Ended August 31,
For a Share Outstanding Throughout Each Period	2025	2024	2023	2022	2021
Net Asset Value, Beginning of Period	$78.83	$75.75	$76.14	$82.67	$82.95
Investment Operations
Net Investment Income1	3.382	2.876	2.094	1.319	1.433
Net Realized and Unrealized Gain (Loss) on Investments	.994	3.043	(.441)	(6.388)	(.250)
Total from Investment Operations	4.376	5.919	1.653	(5.069)	1.183
Distributions
Dividends from Net Investment Income	(3.346)	(2.839)	(2.043)	(1.279)	(1.463)
Distributions from Realized Capital Gains	—	—	—	(.182)	—
Total Distributions	(3.346)	(2.839)	(2.043)	(1.461)	(1.463)
Net Asset Value, End of Period	$79.86	$78.83	$75.75	$76.14	$82.67
Total Return	5.70%	7.99%	2.23%	-6.19%	1.44%
Ratios/Supplemental Data
Net Assets, End of Period (Millions)	$39,358	$35,599	$36,793	$43,723	$41,569
Ratio of Total Expenses to Average Net Assets	0.03%	0.04%	0.04%2	0.04%2	0.04%
Ratio of Net Investment Income to Average Net Assets	4.30%	3.75%	2.78%	1.67%	1.73%
Portfolio Turnover Rate3	73%	69%	63%	50%	42%

1	Calculated based on average shares outstanding.
2	The ratio of expenses to average net assets for the period net of reduction from custody fee offset arrangements was 0.04%.
3	Excludes the value of portfolio securities received or delivered as a result of in-kind purchases or redemptions of the fund’s capital shares, including ETF Creation Units.

Vanguard Intermediate-Term Corporate Bond Index Fund ETF Shares

For a Share Outstanding Throughout Each Period	Year Ended August 31,
For a Share Outstanding Throughout Each Period	2025	2024	2023	2022	2021
Net Asset Value, Beginning of Period	$82.65	$78.27	$79.83	$95.57	$95.98
Investment Operations
Net Investment Income1	3.794	3.429	2.808	2.171	2.163
Net Realized and Unrealized Gain (Loss) on Investments	.755	4.315	(1.605)	(15.176)	(.205)
Total from Investment Operations	4.549	7.744	1.203	(13.005)	1.958
Distributions
Dividends from Net Investment Income	(3.749)	(3.364)	(2.763)	(2.141)	(2.169)
Distributions from Realized Capital Gains	—	—	—	(.594)	(.199)
Total Distributions	(3.749)	(3.364)	(2.763)	(2.735)	(2.368)
Net Asset Value, End of Period	$83.45	$82.65	$78.27	$79.83	$95.57
Total Return	5.70%	10.19%	1.55%	-13.86%	2.08%
Ratios/Supplemental Data
Net Assets, End of Period (Millions)	$57,360	$50,666	$40,262	$41,058	$46,873
Ratio of Total Expenses to Average Net Assets	0.03%	0.04%	0.04%2	0.04%2	0.04%
Ratio of Net Investment Income to Average Net Assets	4.65%	4.32%	3.58%	2.48%	2.27%
Portfolio Turnover Rate3	85%	72%	76%	58%	53%

1	Calculated based on average shares outstanding.
2	The ratio of expenses to average net assets for the period net of reduction from custody fee offset arrangements was 0.04%.
3	Excludes the value of portfolio securities received or delivered as a result of in-kind purchases or redemptions of the fund’s capital shares, including ETF Creation Units.

Vanguard Long-Term Corporate Bond Index Fund ETF Shares

For a Share Outstanding Throughout Each Period	Year Ended August 31,
For a Share Outstanding Throughout Each Period	2025	2024	2023	2022	2021
Net Asset Value, Beginning of Period	$79.31	$75.91	$80.54	$108.31	$107.01
Investment Operations
Net Investment Income1	4.077	3.941	3.692	3.286	3.294
Net Realized and Unrealized Gain (Loss) on Investments2	(3.691)	3.283	(4.727)	(27.794)	1.288
Total from Investment Operations	.386	7.224	(1.035)	(24.508)	4.582
Distributions
Dividends from Net Investment Income	(4.156)	(3.824)	(3.595)	(3.262)	(3.282)
Distributions from Realized Capital Gains	—	—	—	—	—
Total Distributions	(4.156)	(3.824)	(3.595)	(3.262)	(3.282)
Net Asset Value, End of Period	$75.54	$79.31	$75.91	$80.54	$108.31
Total Return	0.57%	9.90%	-1.27%	-23.06%	4.39%
Ratios/Supplemental Data
Net Assets, End of Period (Millions)	$7,198	$13,012	$6,252	$4,545	$5,517
Ratio of Total Expenses to Average Net Assets	0.03%	0.04%	0.04%3	0.04%3	0.04%
Ratio of Net Investment Income to Average Net Assets	5.35%	5.17%	4.79%	3.47%	3.10%
Portfolio Turnover Rate4	44%	33%	33%	31%	36%

1	Calculated based on average shares outstanding.
2	Includes increases from purchase fees of $.00, $.00, $.05, $.01, and $.03.
3	The ratio of expenses to average net assets for the period net of reduction from custody fee offset arrangements was 0.04%.
4	Excludes the value of portfolio securities received or delivered as a result of in-kind purchases or redemptions of the fund’s capital shares, including ETF Creation Units.

Vanguard Mortgage-Backed Securities Index Fund ETF Shares

For a Share Outstanding Throughout Each Period	Year Ended August 31,
For a Share Outstanding Throughout Each Period	2025	2024	2023	2022	2021
Net Asset Value, Beginning of Period	$46.80	$45.23	$47.53	$53.47	$54.36
Investment Operations
Net Investment Income1	1.907	1.740	1.424	.842	.581
Net Realized and Unrealized Gain (Loss) on Investments	(.215)	1.546	(2.344)	(5.995)	(.768)
Total from Investment Operations	1.692	3.286	(.920)	(5.153)	(.187)
Distributions
Dividends from Net Investment Income	(1.922)	(1.716)	(1.380)	(.787)	(.594)
Distributions from Realized Capital Gains	—	—	—	—	(.109)
Total Distributions	(1.922)	(1.716)	(1.380)	(.787)	(.703)
Net Asset Value, End of Period	$46.57	$46.80	$45.23	$47.53	$53.47
Total Return	3.75%	7.49%	-1.94%	-9.71%	-0.35%
Ratios/Supplemental Data
Net Assets, End of Period (Millions)	$14,805	$18,399	$16,343	$14,405	$15,055
Ratio of Total Expenses to Average Net Assets	0.03%	0.04%2	0.04%2	0.04%2	0.04%
Ratio of Net Investment Income to Average Net Assets	4.15%	3.86%	3.10%	1.67%	1.08%
Portfolio Turnover Rate3	91%4	79%	101%	170%	316%

1	Calculated based on average shares outstanding.
2	The ratio of expenses to average net assets for the period net of reduction from custody fee offset arrangements was 0.04%.
3	Includes 68%, 61%, 80%, 113%, and 237%, respectively, attributable to mortgage-dollar-roll activity.
4	Excludes the value of portfolio securities received or delivered as a result of in-kind purchases or redemptions of the fund’s capital shares, including ETF Creation Units.

Additional Information

A Precautionary Note to Investment Companies. Each Funds’ ETF Shares are issued by registered investment companies, and therefore the acquisition of such shares by other investment companies and private funds is subject to the restrictions of Section 12(d)(1) of the Investment Company Act of 1940 (the 1940 Act). SEC Rule 12d1-4 under the 1940 Act permits registered investment companies to invest in other registered investment companies beyond the limits in Section 12(d)(1), subject to certain conditions, including that funds with different investment advisors must enter into a fund of funds investment agreement.

Forum Selection. Each Trust’s Bylaws designate Delaware courts as the exclusive forum for certain claims against or related to the Trust, a trustee, an officer, or other employee of the Trust, except that, unless the Trust otherwise consents in writing, the U.S. Federal District Courts are the exclusive forum for the resolution of complaints under the Securities Act of 1933 or the 1940 Act. These provisions may limit a shareholder’s ability to bring a claim in a different forum and may result in increased shareholder costs in pursuing such a claim.

Shareholder Rights. Each Fund’s Agreement and Declaration of Trust, as amended, requires a shareholder bringing a derivative action on behalf of the Trust that is subject to a pre-suit demand to collectively hold at least 10% of the outstanding shares of the Trust or at least 10% of the outstanding shares of the series or class to which the demand relates and to undertake to reimburse the Trust for the expense of any counsel or advisors used when considering the merits of the demand in the event that the board of trustees determines not to bring such action. In each case, these requirements do not apply to claims arising under the federal securities laws to the extent that any such federal securities laws, rules, or regulations do not permit such application. Each Trust’s Bylaws also provide that shareholders waive the right to trial by jury to the fullest extent permitted by law.

Joint Committed Credit Facility. Each Fund participates, along with other funds managed by Vanguard, in a committed credit facility provided by a syndicate of lenders pursuant to a credit agreement that may be renewed annually; each Vanguard fund is individually liable for its borrowings, if any, under the credit facility. The amount and terms of the committed credit facility are subject to approval by the Board and renegotiation with the lender syndicate on an annual basis.

Securities Market Indexes
Listed below is the broad-based securities market index, as referenced in the Funds’ Average Annual Total Returns tables:

Bloomberg U.S. Aggregate Float Adjusted Index. An index that is the broadest representation of the taxable U.S. bond market, including most U.S. Treasury, agency, corporate, mortgage-backed, asset-backed, and international dollar-denominated issues, all with investment-grade ratings and maturities of 1 year or more. This Index weights its constituent securities based on the value of the constituent securities that are available for public trading, rather than the value of all constituent securities.

Certain affiliates of the Funds and the advisor may purchase and resell ETF Shares pursuant to this Prospectus.

Vanguard Fund	Inception Date	Vanguard Fund Number	CUSIP Number
Vanguard Short-Term Treasury Index Fund
ETF Shares	11/19/2009	3142	92206C102
Vanguard Intermediate-Term Treasury Index Fund
ETF Shares	11/19/2009	3143	92206C706
Vanguard Long-Term Treasury Index Fund
ETF Shares	11/19/2009	3144	92206C847
Vanguard Short-Term Corporate Bond Index Fund
ETF Shares	11/19/2009	3145	92206C409
Vanguard Intermediate-Term Corporate Bond Index Fund
ETF Shares	11/19/2009	3146	92206C870
Vanguard Long-Term Corporate Bond Index Fund
ETF Shares	11/19/2009	3147	92206C813
Vanguard Mortgage-Backed Securities Index Fund
ETF Shares	11/19/2009	3148	92206C771

Inception Date means the date on which the assets of a fund (or one of its share classes) are first invested in accordance with the fund’s investment objective. For funds with a subscription period, the inception date is the day after that period ends. Investment performance is generally measured from the inception date.

CGS identifiers have been provided by CUSIP Global Services, managed on behalf of the American Bankers Association by FactSet Research Systems Inc., and are not for use or dissemination in a manner that would serve as a substitute for any CUSIP service. The CUSIP Database, © 2026 American Bankers Association. “CUSIP” is a registered trademark of the American Bankers Association.

CFA® is a registered trademark owned by CFA Institute.

“Bloomberg®” and Bloomberg US Treasury 1–3 Year Index, Bloomberg U.S. Treasury 3–10 Year Index, Bloomberg U.S. Long Treasury Index, Bloomberg U.S. 1-5 Year Corporate Bond Index, Bloomberg U.S. 5–10 Year Corporate Bond Index, Bloomberg U.S. 10+ Year Corporate Bond Index, and Bloomberg U.S. MBS Float Adjusted Index (the “indices”) are service marks of Bloomberg Finance L.P. and its affiliates, including Bloomberg Index Services Limited (“BISL”), the administrator of the Index (collectively, “Bloomberg”), and have been licensed for use for certain purposes by Vanguard.

Vanguard Sector Bond Index Funds (the “Funds”) are not sponsored, endorsed, sold or promoted by Bloomberg. Bloomberg does not make any representation or warranty, express or implied, to the owners of or counterparties to the Funds or any member of the public regarding the advisability of investing in securities or commodities generally or in the Funds particularly. The only relationship of Bloomberg to Vanguard is the licensing of certain trademarks, trade names and service marks and of the indices, which are determined, composed and calculated by BISL without regard to Vanguard or the Funds. Bloomberg has no obligation to take the needs of Vanguard or the owners of the Funds into consideration in determining, composing or calculating the indices. Bloomberg is not responsible for and has not participated in the determination of the timing, price, or quantities of the Funds to be issued. Bloomberg shall not have any obligation or liability, including, without limitation, to customers of the Funds, in connection with the administration, marketing or trading of the Funds.

BLOOMBERG DOES NOT GUARANTEE THE ACCURACY AND/OR THE COMPLETENESS OF THE INDICES OR ANY DATA RELATED THERETO AND SHALL HAVE NO LIABILITY FOR ANY ERRORS, OMISSIONS OR INTERRUPTIONS THEREIN. BLOOMBERG DOES NOT MAKE ANY WARRANTY, EXPRESS OR IMPLIED, AS TO RESULTS TO BE OBTAINED BY VANGUARD, OWNERS OF THE FUNDS OR ANY OTHER PERSON OR ENTITY FROM THE USE OF THE INDICES OR ANY DATA RELATED THERETO. BLOOMBERG DOES NOT MAKE ANY EXPRESS OR IMPLIED WARRANTIES AND EXPRESSLY DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE WITH RESPECT TO THE INDICES OR ANY DATA RELATED THERETO. WITHOUT LIMITING ANY OF THE FOREGOING, TO THE MAXIMUM EXTENT ALLOWED BY LAW, BLOOMBERG, ITS LICENSORS, AND ITS AND THEIR RESPECTIVE EMPLOYEES, CONTRACTORS, AGENTS, SUPPLIERS, AND VENDORS SHALL HAVE NO LIABILITY OR RESPONSIBILITY WHATSOEVER FOR ANY INJURY OR DAMAGES—WHETHER DIRECT, INDIRECT, CONSEQUENTIAL, INCIDENTAL, PUNITIVE OR OTHERWISE—ARISING IN CONNECTION WITH THE FUNDS OR INDICES OR ANY DATA OR VALUES RELATING THERETO—WHETHER ARISING FROM THEIR NEGLIGENCE OR OTHERWISE, EVEN IF NOTIFIED OF THE POSSIBILITY THEREOF.

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For More Information

If you would like more information about Vanguard Sector Bond ETFs, the following documents are available free upon request:

Annual/Semiannual Reports to Shareholders and Form N-CSR

Additional information about the Funds’ investments is available in the Funds’ annual and semiannual reports to shareholders and in Form N-CSR. In the annual reports, you will find a discussion of the market conditions and investment strategies that significantly affected the Funds’ performance during their last fiscal year. In Form N-CSR, you will find the Funds’ annual and semiannual financial statements.

Statement of Additional Information (SAI)

The SAI provides more detailed information about the Funds’ ETF Shares and is incorporated by reference into (and thus legally a part of) this Prospectus.

To obtain a free copy of the latest annual or semiannual reports, financial statements, or the SAI, or to request additional information about Vanguard ETF Shares, please visit https://vgi.vg/fund-literature or contact us as follows:

Telephone: 866-499-8473; Text telephone for people with hearing impairment: 800-749-7273

Information Provided by the SEC

Reports and other information about the Funds are available in the EDGAR database on the SEC’s website at sec.gov, or you can receive copies of this information, for a fee, by electronic request at the following email address: [email protected].

Funds’ Investment Company Act file number: 811-07803

Vanguard Marketing Corporation, Distributor.

P 3142 062026

Vanguard Fund	Vanguard ETF Shares
Vanguard Short-Term Treasury Index Fund	Vanguard Short-Term Treasury ETF
Vanguard Intermediate-Term Treasury Index Fund	Vanguard Intermediate-Term Treasury ETF
Vanguard Long-Term Treasury Index Fund	Vanguard Long-Term Treasury ETF
Vanguard Short-Term Corporate Bond Index Fund	Vanguard Short-Term Corporate Bond ETF
Vanguard Intermediate-Term Corporate Bond Index Fund	Vanguard Intermediate-Term Corporate Bond ETF
Vanguard Long-Term Corporate Bond Index Fund	Vanguard Long-Term Corporate Bond ETF
Vanguard Mortgage-Backed Securities Index Fund	Vanguard Mortgage-Backed Securities ETF

Vanguard Fund	Number of Bonds in Fund	Number of Bonds in Target Index
Vanguard Short-Term Treasury Index Fund	94	96
Vanguard Intermediate-Term Treasury Index Fund	103	104
Vanguard Long-Term Treasury Index Fund	94	94
Vanguard Short-Term Corporate Bond Index Fund	2,594	3,166
Vanguard Intermediate-Term Corporate Bond Index Fund	2,130	2,237
Vanguard Long-Term Corporate Bond Index Fund	1,847	3,083
Vanguard Mortgage-Backed Securities Index Fund	1,4571	1,049