Summary Prospectus by Investment Company - Form 497K

Vanguard Variable Insurance Funds

Balanced Portfolio

Summary Prospectus

April 26, 2024

The Portfolio's statutory Prospectus and Statement of Additional Information dated April 26, 2024, 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 Portfolio's Prospectus, which contains more information about the Portfolio and its risks. You can find the Portfolio's Prospectus and other information about the Portfolio 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

The Portfolio seeks to provide long-term capital appreciation and reasonable current income.

Fees and Expenses

The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the Portfolio. 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 Portfolio Operating Expenses
(Expenses that you pay each year as a percentage of the value of your investment)

Management Fees	0.20 %
12b-1 Distribution Fee	None
Other Expenses	0.01 %
Total Annual Portfolio Operating Expenses	0.21 %

Example

The following example is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you were to invest $10,000 in the Portfolio's shares. This example assumes that the Portfolio provides a return of 5% each year and that total annual portfolio operating expenses remain as stated in the preceding table. You would incur these hypothetical expenses whether or not you were to redeem your investment at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 Year	3 Years	5 Years	10 Years
$22	$68	$118	$268

Portfolio Turnover

The Portfolio 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 portfolio operating expenses or in the previous expense example, reduce the Portfolio's performance. During the most recent fiscal year, the Portfolio's turnover rate was 40% of the average value of its portfolio.

Principal Investment Strategies

Vanguard Variable Insurance Funds Balanced Portfolio (the Balanced Portfolio) invests 60% to 70% of its assets in dividend-paying and, to a lesser extent, non-dividend-paying common stocks of established large companies. In choosing these stocks, the advisor seeks durable businesses that appear to be undervalued but have prospects for improvement. These stocks are commonly referred to as value stocks. The remaining 30% to 40% of the Portfolio's assets are invested mainly in fixed income securities that the advisor believes will generate a moderate level of current income. These securities include investment-grade corporate bonds, with some exposure to U.S. Treasury and government agency bonds, and mortgage-backed securities.

Principal Risks

The Portfolio is subject to the risks associated with the stock and bond markets, any of which could cause an investor to lose money, and the level of risk may vary based on market conditions. However, because stock and bond prices can move in different directions or to different degrees, the Portfolio's bond holdings may counteract some of the volatility experienced by the Portfolio's stock holdings. The Portfolio is subject to the following risks, which could affect the Portfolio's performance:

• Investment style risk, which is the chance that returns from large-capitalization value stocks will trail returns from the overall stock market. Large-cap stocks tend to go through cycles of doing better-or worse-than other segments of the stock market or the stock market in general. These periods have, in the past, lasted for as long as several years.

• Stock market risk, which is the chance that stock prices overall will decline. Stock markets tend to move in cycles, with periods of rising prices and periods of falling prices.

• Income risk, which is the chance that the Portfolio's income will decline because of falling interest rates. A fund holding bonds will experience a decline in income when interest rates fall because the fund then must invest new cash flow and cash from maturing bonds in lower-yielding bonds.

• Interest rate risk, which is the chance that bond prices overall will decline because of rising interest rates. Interest rate risk should be moderate for the Portfolio because the Portfolio invests only a portion of its assets in bonds and because the average duration of the Portfolio's bond portfolio is generally intermediate-term. The prices of short- and intermediate-term bonds are less sensitive to interest rate changes than the prices of long-term bonds.

• Credit risk, which is the chance that a bond issuer will fail to pay interest or principal in a timely manner or that negative perceptions of the issuer's ability to

make such payments will cause the price of that bond to decline. Credit risk should be low for the Portfolio because it invests only a portion of its assets in bonds, most of which are considered to be of high quality.

• Call risk, which is the chance that during periods of falling interest rates, issuers of callable bonds may call (redeem) securities with higher coupon rates or interest rates before their maturity dates. The Portfolio would then lose any price appreciation above the bond's call price and would be forced to reinvest the unanticipated proceeds at lower interest rates, resulting in a decline in the Portfolio's income. Such redemptions and subsequent reinvestments would also increase the Portfolio's turnover rate. For mortgage-backed securities, this risk is known as prepayment risk.

• Liquidity risk, which is the chance that the Fund may not be able to sell a security in a timely manner at a desired price.

• Manager risk, which is the chance that poor security selection will cause the Portfolio to underperform relevant benchmarks or other funds with a similar investment objective.

An investment in the Portfolio is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Annual Total Returns

The following bar chart and table are intended to help you understand the risks of investing in the Portfolio. The bar chart shows how the performance of the Portfolio has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Portfolio compare with those of relevant market indexes and a composite stock/bond index, which have investment characteristics similar to those of the Portfolio. The Composite Stock/Bond Index is weighted 65% in the S&P 500 Index and 35% in the Bloomberg U.S. Credit A or Better Bond Index. The Portfolio'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 Portfolio's returns, the returns would be lower. Keep in mind that the Portfolio's past performance does not indicate how the Portfolio will perform in the future. Updated performance information is available on our website for Financial Advisors at advisors.vanguard.com or by calling Vanguard toll-free at 800-522-5555.

Annual Total Returns - Balanced Portfolio

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

	Total Return	Quarter
Highest	12.21 %	June 30, 2020
Lowest	-13.84 %	March 31, 2020

Average Annual Total Returns for Periods Ended December 31, 2023

	1 Year	5 Years	10 Years
Balanced Portfolio	14.33 %	9.59 %	7.89 %
Composite Stock/Bond Index (reflects no deduction for fees, expenses, or taxes)	19.36 %	10.96 %	8.81 %
Dow Jones U.S. Total Stock Market Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)	26.06	15.05	11.40
Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)	5.53	1.10	1.81

Investment Advisor

Wellington Management Company LLP (Wellington Management)

Portfolio Managers

Loren L. Moran, CFA, Senior Managing Director and Fixed Income Portfolio Manager of Wellington Management. She has managed the fixed income portion of the Portfolio since 2021 (co-managed since 2017).

Daniel J. Pozen, Senior Managing Director and Equity Portfolio Manager of Wellington Management. He has managed the stock portion of the Portfolio since 2019.

Tax Information

The Portfolio normally distributes its net investment income and net realized capital gains, if any, to its shareholders, which are the insurance company separate accounts that sponsor your variable annuity or variable life insurance contract. The tax consequences to you of your investment in the Portfolio depend on the provisions of the annuity or life insurance contract through which you invest. For more information on taxes, please refer to the prospectus of the annuity or life insurance contract through which Portfolio shares are offered.

Payments to Financial Intermediaries

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