T. Rowe Price Equity Index 500 Fund

T. ROWE PRICE<br/><br/>Equity Index 500 Fund<br/><br/>Investor Class<br/><br/>I Class<br/><br/>SUMMARY

Investment Objective

The fund seeks to track the performance of a benchmark index that measures the investment return of large-capitalization U.S. stocks.

Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table.

Fees and Expenses of the Fund<br/><br/><b>Shareholder fees (fees paid directly from your investment)</b>

Shareholder Fees - T. Rowe Price Equity Index 500 Fund - USD ($)	Investor Class		I Class
Maximum account fee	$ 20	[1]

<b>Annual fund operating expenses<br/> (expenses that you pay each year as a<br/> percentage of the value of your investment)</b>

Annual Fund Operating Expenses - T. Rowe Price Equity Index 500 Fund	Investor Class		I Class
Management fees	0.06%		0.06%
Distribution and service (12b-1) fees
Other expenses	0.14%
Total annual fund operating expenses	0.20%	[1]	0.06%
Fee waiver/expense reimbursement	0.01%	[1]
Total annual fund operating expenses after fee waiver/expense reimbursement	0.21%	[1]	0.06%

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual 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, that your investment has a 5% return each year, and that the fund’s operating expenses remain the same. The example also assumes that an expense limitation arrangement currently in place is not renewed; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - T. Rowe Price Equity Index 500 Fund - USD ($)	1 year	3 years	5 years	10 years
Investor Class	22	68	118	268
I Class	6	19	34	77

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when the fund’s 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 7.3% of the average value of its portfolio.

Investments, Risks, and Performance<br/><br/>Principal Investment Strategies

The fund attempts to match the investment return of large-capitalization U.S. stocks by seeking to match the performance of its benchmark index, the S&P 500 Index. The fund uses a full replication strategy, which involves investing substantially all of its assets in all of the stocks in the S&P 500 and seeking to maintain holdings of each stock in proportion to its weight in the index.

The S&P 500 is made up of primarily large-capitalization companies that represent a broad spectrum of the U.S. economy and a substantial part of the U.S. stock market’s total capitalization. (Market capitalization is the number of a company’s outstanding shares multiplied by the market price per share.)

Using a committee process, S&P Dow Jones Indices LLC (“SPDJI”) constructs the benchmark index by applying certain eligibility factors to common stocks of U.S. companies. Eligibility factors include, but are not limited to, domicile, exchange listing, organizational structure and share type, market capitalization, liquidity, ownership (investable weight factor), sector representation, and financial viability. Index constituents are weighted by float-adjusted market capitalization.

Under normal conditions, the fund will invest at least 80% of its net assets (including any borrowings for investment purposes) in stocks that are included in its benchmark index. T. Rowe Price compares the composition of the fund to that of the index. If a material misweighting develops, the portfolio manager seeks to rebalance the portfolio in an effort to realign it with its index.

While most assets will be invested in common stocks, the fund may also purchase stock index futures contracts. Futures would typically be used to reduce cash balances in the fund and increase the level of fund assets exposed to common stocks represented in the fund’s benchmark index. In addition, the fund lends its portfolio securities as a means of generating additional income.

While there is no guarantee, the correlation between the fund and its benchmark index is expected to be at least 0.95. A correlation of 1.00 indicates that the returns of the fund and the index will always move in the same direction (but not necessarily by the same amount). A correlation of 0.00 would mean price movements in the fund are unrelated to price movements in the index.

The fund may sell securities to better align its portfolio with the characteristics of its benchmark index or to satisfy redemption requests. The fund will generally seek to sell securities that have been removed from the benchmark index within a reasonable timeframe taking into consideration market conditions.

Principal Risks

As with any mutual fund, there is no guarantee that the fund will achieve its objective. The fund’s share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund are summarized as follows:

Risks of U.S. stock investing Common stocks generally fluctuate in value more than bonds and may decline significantly over short time periods. There is a chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising and falling prices. The value of a stock in which the fund invests may decline due to general weakness in the U.S. stock market, such as when the U.S. financial markets decline, or because of factors that affect a particular company or industry.

Market capitalization risks Although stocks issued by larger companies tend to have less overall volatility than stocks issued by smaller companies, larger companies may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods. In addition, larger companies may be less capable of responding quickly to competitive challenges and industry changes, and may suffer sharper price declines as a result of earnings disappointments.

Index investing risks Because the fund is passively managed and seeks to match the performance of its benchmark index, holdings are generally not reallocated based on changes in market conditions or outlook for a specific security, industry, or market sector. As a result, the fund’s performance may lag the performance of actively managed funds.

Tracking error risks The returns of the fund are expected to be slightly below the returns of its benchmark index (referred to as “tracking error”) because the fund incurs fees and transaction expenses while the index has no fees or expenses. The risk of tracking error is increased to the extent the fund is unable to fully replicate its benchmark index, which could result from changes in the composition of the index or the timing of purchases and redemptions of fund shares.

Futures risks The fund’s use of stock index futures exposes it to potential volatility and losses in excess of direct investments in the contract’s underlying assets. The values of the fund’s positions in stock index futures tend to fluctuate in response to changes in the value of the underlying index, which exposes the fund to the risk that the underlying index will not move in a direction that is favorable to the fund. While the value of a stock index futures contract tends to correlate with the value of the underlying index, differences between the futures market and the value of the underlying index may result in an imperfect correlation. Since losses could result from market movement, the fund may need to sell other portfolio securities at disadvantageous times in order to meet daily margin requirements. The futures markets may experience reduced liquidity, which could result in losses to the fund and cause the fund to be unable to settle its futures positions.

Securities lending risks Securities lending involves the risk that the fund may lose money because the borrower of the loaned securities fails to return the securities to the fund in a timely manner or not at all. The fund may also lose money if there is a decline in the value of the collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. In addition, securities lending activities may cause adverse tax consequences for the fund.

Performance

The following performance information provides some indication of the risks of investing in the fund. The fund’s performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund’s Investor Class. Returns for other share classes vary since they have different expenses.

<b>EQUITY INDEX 500 FUND<br/>Calendar Year Returns</b>

	Quarter Ended	Total Return		Quarter Ended	Total Return
Best Quarter	6/30/09	15.99%	Worst Quarter	9/30/11	-13.92%

The following table shows the average annual total returns for each class of the fund that has been in operation for at least one full calendar year, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund, if applicable.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA. After-tax returns are shown only for the Investor Class and will differ for other share classes.

<b>Average Annual Total Returns</b><br/><br/><b>Periods ended </b><br/><b>December 31, 2018</b>

Average Annual Total Returns - T. Rowe Price Equity Index 500 Fund	1 Year	5 Years	10 Years	Since inception		Inception date
Investor Class	(4.58%)	8.24%	12.85%			Mar. 30, 1990
Investor Class | Returns after taxes on distributions	(5.14%)	7.70%	12.39%			Mar. 30, 1990
Investor Class | Returns after taxes on distributions and sale of fund shares	(2.29%)	6.44%	10.72%			Mar. 30, 1990
I Class	(4.44%)			9.31%		Aug. 28, 2015
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	(4.38%)	8.49%	13.12%	9.40%	[1]	Aug. 28, 2015

Updated performance information is available through troweprice.com.

[1] Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee.

[1] T. Rowe Price Associates, Inc., has agreed (through April 30, 2020) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the class’ ratio of expenses to average daily net assets to exceed 0.21%. The agreement may be terminated at any time beyond April 30, 2020, with approval by the fund’s Board of Directors. Fees waived and expenses paid under this agreement (and previous limitations of 0.25% and 0.30%) are subject to reimbursement to T. Rowe Price Associates, Inc., by the fund whenever the class’ expense ratio is below 0.21%. However, no reimbursement will be made more than three years from the date such amounts were initially waived or reimbursed. The fund may only make repayments to T. Rowe Price Associates, Inc., if such repayment does not cause the class’ expense ratio (after the repayment is taken into account) to exceed the lesser of: (1) the expense limitation in place at the time such amounts were waived; or (2) the class’ current expense limitation.

[1] Return since 8/28/15.