Summary Prospectus by Investment Company (Form 497K)

April 28, 2026

Summary Prospectus

Vanguard Variable Insurance Funds

Short-Term Investment-Grade Portfolio

The Fund's statutory Prospectus and Statement of Additional Information dated April 28, 2026, as may be amended or supplemented, are incorporated into and made part of this Summary Prospectus by reference.

Before you invest, you may want to review the Fund's Prospectus, which contains more information about the Fund and its risks. You can find the Fund's Prospectus and other information about the Fund online at www.vanguard.com/prospectus. You can also obtain this information at no cost by calling 800-522-5555 or by sending an email request to [email protected].

The Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Investment Objective

Vanguard Variable Insurance Funds Short-Term Investment-Grade Portfolio (the "Fund") seeks to provide current income while maintaining limited price volatility.

Fees and Expenses

The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the Fund. The expenses shown in the table and in the example that follows do not reflect additional fees and expenses associated with the annuity or life insurance program through which you invest. If those additional fees and expenses were included, overall expenses would be higher.

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

Management Fees	0.13 %
12b-1 Distribution Fee	None
Other Expenses	0.01 %
Total Annual Fund Operating Expenses	0.14 %

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
$14	$45	$79	$179

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. 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 104% of the average value of its portfolio.

Principal Investment Strategies

The Fund employs an active management approach. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in investment-grade fixed income securities (which include high- and medium-quality fixed income securities). For purposes of the 80% policy, investment-grade fixed income securities are those rated the equivalent of Baa3 and above by Moody's or another independent rating agency or, if unrated, are determined to be of comparable quality by the Fund's advisor. The Fund expects to maintain a dollar-weighted average maturity between 1 and 4 years. The Fund may invest in derivatives such as options, futures contracts, and swap agreements.

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.

• 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.

• 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.

• Active Management. The Fund is actively managed. The advisor's security selection and/or strategy execution could cause the Fund to underperform relevant securities markets or other funds with a similar investment objective.

• 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 the 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.

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 has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Fund compare with those of a broad-based securities market index and one or more additional indexes with similar investment characteristics as the Fund. The Fund's returns are net of its expenses but do not reflect additional fees and expenses that are deducted by the annuity or life insurance program through which you invest. If such fees and expenses were included in the calculation of the Fund's returns, the returns would be lower. Keep in mind that the Fund's past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website for Financial Advisors at advisors.vanguard.com.

Annual Total Returns - Short-Term Investment-Grade Portfolio   

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

	Total Return	Quarter
Highest	4.80 %	June 30, 2020
Lowest	-3.73 %	March 31, 2022

Average Annual Total Returns for Periods Ended December 31, 2025 

	1 Year	5 Years	10 Years
Short-Term Investment-Grade Portfolio	6.85 %	2.23 %	2.81 %
Bloomberg U.S. 1-5 Year Credit Bond Index (reflects no deduction for fees, expenses, or taxes)	6.74 %	2.15 %	2.84 %
Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)	7.30	-0.36	2.01

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

Arvind Narayanan, CFA, Principal of Vanguard and Senior Portfolio Manager at VCM. He has co-managed the Fund since 2019.

Thanh Nguyen, CFA, Portfolio Manager at VCM. She has co-managed the Fund since April 2026.

Daniel Shaykevich, Principal of Vanguard and Senior Portfolio Manager at VCM. He has co-managed the Fund since 2018.

Purchase and Sale of Fund Shares

The Fund offers its shares only to separate accounts of insurance companies to fund annuity or life insurance contracts. You cannot purchase shares of the Fund directly, but only through an annuity or life insurance contract offered by an insurance company. For information regarding how you, as a contract owner,