Mid-Cap Index Portfolio

Mid-Cap Index Portfolio

Investment Objective

The Portfolio seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization stocks.

Fees and Expenses

The following table describes the fees and expenses you may pay if you buy and hold shares of the Portfolio. The expenses shown in the table and in the example that follow 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)

Annual Portfolio Operating Expenses	Mid-Cap Index Portfolio Mid-Cap Index Portfolio
Management Fees	0.16%
12b-1 Distribution Fee	none
Other Expenses	0.03%
Total Annual Portfolio Operating Expenses	0.19%

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 redeem your investment at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
Mid-Cap Index Portfolio | Mid-Cap Index Portfolio | USD ($)	19	61	107	243

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 21% of the average value of its portfolio.

Principal Investment Strategies

The Portfolio employs an indexing investment approach designed to track the performance of the CRSP US Mid Cap Index, a broadly diversified index of stocks of mid-size U.S. companies. The Portfolio attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Principal Risks

An investment in the Portfolio could lose money over short or even long periods. You should expect the Portfolio’s share price and total return to fluctuate within a wide range. The Portfolio is subject to the following risks, which could affect the Portfolio’s performance:

• Stock market risk, which is the chance that stock prices overall will decline. Stock markets tend to move in cycles, with periods of rising prices and periods of falling prices. The Portfolio’s target index tracks a subset of the U.S. stock market, which could cause the Portfolio to perform differently from the overall stock market. In addition, the Portfolio’s target index may, at times, become focused in stocks of a particular market sector, which would subject the Portfolio to proportionately higher exposure to the risks of that sector.

• Investment style risk, which is the chance that returns from mid-capitalization stocks will trail returns from the overall stock market. Historically, mid-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

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 the Portfolio’s target index and other comparative indexes, which have investment characteristics similar to those of the Portfolio. 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 — Mid-Cap Index Portfolio

During the periods shown in the bar chart, the highest return for a calendar quarter was 21.44% (quarter ended September 30, 2009), and the lowest return for a quarter was –25.65% (quarter ended December 31, 2008).

Average Annual Total Returns for Periods Ended December 31, 2016

Average Annual Total Returns - Mid-Cap Index Portfolio		1 Year	5 Years	10 Years
Mid-Cap Index Portfolio		11.11%	14.22%	7.55%
MSCI US Mid Cap 450 Index	[1]	12.62%	14.98%	7.96%
Spliced Mid Cap Index	[1]	11.25%	14.42%	7.70%
CRSP US Mid Cap Index	[1]	11.25%	14.56%

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