|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |   |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |   |
| SUMMARYPROSPECTUS                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |   |
| PRDMX                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |   |
| May 1,2014                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |   |
| T. Rowe Price

DiversifiedMid-Cap Growth Fund                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| A fund seeking long-termcapital growth through a broadly diversified portfolio of mid-cap growth stocks.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| 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 prospectusand other information about the fund online at troweprice.com/prospectus. You can also get this information at no cost by calling1-800-225-5132or by sending an e-mail request to info@troweprice.com. This Summary Prospectus incorporates by reference the fund’sprospectus, dated May 1, 2014, and Statement of Additional Information, dated May 1, 2014.

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

|    |   |
|---------|--------|
| Summary | 1      |

Investment Objective

The fund seeks to provide long-term capital growth by investingprimarily in the common stocks of mid-cap growth companies.

Fees and Expenses

This table describes the feesand expenses that you may pay if you buy and hold shares of the fund. 

Fees and Expenses of the Fund

|                                                                                                          |   |
|---------------------------------------------------------------------------------------------------------------|--------|
| Shareholder fees (fees paiddirectly from your investment)                                                     |
| Maximum sales charge (load) imposed on purchases                                                              | NONE   |
|                                                                                                          |   |
| Maximum deferred sales charge (load)                                                                          | NONE   |
|                                                                                                          |   |
| Redemption fee                                                                                                | NONE   |
|                                                                                                          |   |
| Maximum account fee                                                                                           | $20a   |
| Annual fund operating expenses(expenses that you pay each yearas apercentage of the value of your investment) |
| Management fees                                                                                               | 0.64%  |
|                                                                                                          |   |
| Distribution and service (12b-1) fees                                                                         | 0.00%  |
|                                                                                                          |   |
| Other expenses                                                                                                | 0.27%  |
|                                                                                                          |   |
| Total annualfund operating expenses                                                                           | 0.91%  |

a Subjectto certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee.

Example  This example is intendedto 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 redeemall of your shares at the end of those periods. The example also assumes that your investment has a 5%return each year and the fund’s operating expenses remain the same. Although your actual costs maybe higher or lower, based on these assumptions your costs would be:

|   |    |    |     |
|--------|---------|---------|----------|
| 1 year | 3 years | 5 years | 10 years |
| $93    | $290    | $504    | $1,120   |

Portfolio Turnover  The fundpays 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 resultin higher taxes when fund shares are held in a taxable account. These costs, which are not reflectedin annual fund operating expenses or in the example, affect the fund’s performance. During the mostrecent fiscal year, the fund’s portfolio turnover rate was 17.7% of the average value of its portfolio.

|         |   |
|--------------|--------|
| T.Rowe Price | 2      |

Investments, Risks, and Performance

Principal Investment Strategies  The fund will normally investat least 80% of its net assets (including any borrowings for investment purposes) in a broadly diversifiedportfolio of common stocks of mid-cap growth companies. T. Rowe Price expects the earnings of these companiesto grow at a faster rate than the average company. The fund defines mid-cap companies as those whosemarket capitalization falls within the range of either the S&P MidCap 400 Index or the Russell MidcapGrowth Index. As of December 31, 2013, the market capitalization ranges for the S&P MidCap 400 Indexand the Russell Midcap Growth Index were approximately $717.6 million to $11.5 billion, and $441.7 millionto $29.2 billion, respectively. (A company’s market capitalization is determined by multiplyingits shares outstanding by its stock price.)

The fund has the flexibility to purchase some larger and smallercompanies that have qualities consistent with the portfolio’s core characteristics. In other words,the fund may on occasion purchase a stock whose market capitalization is outside of the capitalizationrange of mid-cap companies. The market capitalization of the companies in the fund’s portfolio,the S&P MidCap 400 Index, and the Russell Midcap Growth Index will change over time, and the fundwill not automatically sell or cease to purchase a stock of a company it already owns just because thecompany’s market capitalization grows or falls outside of the index ranges. The portfolio will bevery broadly diversified, and the top 25 holdings will not constitute a large portion of assets. Thisbroad diversification should help reduce the effects of individual security price volatility on overallfund performance.

Stock selection is based on a combination of fundamental, bottom-up analysis and top-downquantitative strategies in an effort to identify companies with superior long-term appreciation prospects.We generally use a growth approach, looking for companies with one or more of the following characteristics:

· ademonstrated ability to consistently increase revenues, earnings, and cash flow;

· capable management;

· attractivebusiness niches; and

· a sustainable competitive advantage.

Valuation measures, such asa company’s price/earnings (P/E) ratio relative to the market and its own growth rate, are alsoconsidered. We will typically limit holdings of high-yielding stocks, but the payment of dividends—evenabove-average dividends—does not disqualify a stock from consideration. Most holdings are expectedto have relatively low dividend yields.

In pursuing its investment objective, the fund’s managementhas the discretion to purchase some securities that do not meet its normal investment criteria, as describedabove, when it perceives an unusual opportunity for gain. These special situations might arise when thefund’s management believes a security could increase in value for a variety of reasons, includinga change in management, an extraordinary 

|    |   |
|---------|--------|
| Summary | 3      |

corporateevent, or a temporary imbalance in the supply of or demand for the securities.

While most assets will typicallybe invested in U.S. common stocks, the fund may invest in foreign stocks in keeping with the fund’sobjectives.

The fund may sell securities for a variety of reasons, such as to secure gains, limitlosses, or redeploy assets into more promising opportunities.

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

Active management riskThe fund is subject to the risk that the investment adviser’sjudgments about the attractiveness, value, or potential appreciation of the fund’s investments mayprove to be incorrect. If the securities selected and strategies employed by the fund fail to producethe intended results, the fund could underperform other funds with similar objectives and investmentstrategies.

Risks of stockinvesting  Stocks generally fluctuate in value more than bonds and may decline significantly overshort time periods. There is a chance that stock prices overall will decline because stock markets tendto move in cycles, with periods of rising prices and falling prices. The value of a stock in which thefund invests may decline due to general weakness in the stock market or because of factors that affecta company or a particular industry. 

Marketcapitalization risk  Investing primarily in issuers within the same market capitalization categorycarries the risk that the category may be out of favor due to current market conditions or investor sentiment.Because the fund invests primarily in securities issued by mid-cap companies, it is likely to be morevolatile than a fund that focuses on securities issued by large companies. Medium-sized companies typicallyhave less seasoned management, narrower product lines, and less capital reserves and liquidity than largercompanies, and are therefore more sensitive to economic, market, and industry changes.

Investment style risk  Different investment styles tend toshift in and out of favor, depending on market conditions and investor sentiment. The fund’s growthapproach to investing could cause it to underperform other stock funds that employ a different investmentstyle. Growth stocks tend to be more volatile than certain other types of stocks and their prices usuallyfluctuate more dramatically than the overall stock market. A stock with growth characteristics can havesharp price declines due to decreases in current or expected earnings and may lack dividends that canhelp cushion its share price in a declining market.

Foreign investing risk  This is the risk that the fund’s investments inforeign securities may be adversely affected by political, social, and economic conditions overseas,reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

|         |   |
|--------------|--------|
| T.Rowe Price | 4      |

Performance The bar chart showing calendar year returns and the average annual total returns table indicate riskby illustrating how much returns can differ from one year to the next and how fund performance compareswith that of a comparable market index. The fund’s past performance (before and after taxes) isnot necessarily an indication of future performance.

The fund can also experience short-term performanceswings, as shown by the best and worst calendar quarter returns during the years depicted.

Inaddition, the average annual total returns table shows hypothetical after-tax returns to suggest howtaxes paid by a shareholder may influence returns. After-tax returns are calculated using the historicalhighest individual federal marginal income tax rates and do not reflect the impact of state and localtaxes. Actual after-tax returns depend on an investor’s tax situation and may differ from thoseshown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferredarrangements, such as a 401(k) account or individual retirement account.

|    |   |
|---------|--------|
| Summary | 5      |

|                        |                                                                            |                                 |              |   |        |          |       |        |           |   |   |   |
|-----------------------------|---------------------------------------------------------------------------------|--------------------------------------|-------------------|--------|-------------|---------------|------------|-------------|----------------|--------|--------|--------|
| AverageAnnual Total Returns |                                                                            |                                 |              |   |        |          |       |        |           |   |
|                        |                                                                            |                                 | Periodsended      |   |
|                        |                                                                            |                                 | December 31, 2013 |   |
|                        |                                                                            |                                 | 1 Year       |   |        | 5 Years  |       |        | 10 Years  |   |   |   |
|                        | Diversified Mid-Cap Growth Fund                                                 |                                 |              |   |        |          |       |        |           |   |   |
|                        |                                                                            | Returns before taxes                 | 34.57        | %      | 22.75  | %             | 9.32  | %           |           |
|                        |                                                                            | Returns after taxes on distributions | 34.54        |   |        | 22.73    |       |        | 9.17      |   |   |   |
|                        |                                                                            | Returns after taxes on distributions |              |   |        |          |       |        |           |   |   |   |
|                        |                                                                            | and sale of fund shares              | 19.58        |   |        | 18.75    |       |        | 7.67      |   |   |   |
|                        | Russell Midcap Growth Index(reflects no deduction for fees, expenses, or taxes) | 35.74                           |              |   | 23.37  |          |       | 9.77   |           |   |   |
|                        | S&P MidCap 400 Index (reflectsno deduction for fees, expenses, or taxes)    | 33.50                           |              |   | 21.89  |          |       | 10.36  |           |   |   |
|                        | LipperMid-Cap Growth Funds Index                                                | 36.52                           |              |   | 21.31  |          |       | 9.49   |           |   |   |

Updated performance information is available through troweprice.com or may be obtainedby calling 1-800-225-5132.

Management

Investment Adviser  T. Rowe Price Associates, Inc. (T. Rowe Price)

|              |                                        |               |                      |
|-------------------|---------------------------------------------|--------------------|---------------------------|
| Portfolio Manager | Title                                       | Managed Fund Since | Joined Investment Adviser |
| DonaldJ. Easley   | Co-Chairman ofInvestment Advisory Committee | 2009               | 2000                      |
| Donald J. Peters  | Co-Chairman ofInvestmentAdvisory Committee  | 2003               | 1993                      |

Purchaseand Sale of Fund Shares

The fund’s investment minimums generally are as follows (if you hold shares througha financial intermediary, the intermediary may impose different investment minimums):

|                                                                                                                                               |                     |                       |
|----------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------|----------------------------|
| Type of Account                                                                                                                                    | Minimum initial purchase | Minimum subsequentpurchase |
| Individualretirement accounts, small business retirement plan accounts, and Uniform Gifts to Minors Act or UniformTransfers to Minors Act accounts | $1,000                   | $100                       |
|                                                                                                                                               |                     |                       |
| All other accounts                                                                                                                                 |   2,500        |    100      |

Youmay purchase, redeem, or exchange shares of the fund on any day the New York Stock Exchange is open forbusiness by accessing your account online at troweprice.com, by calling 1-800-225-5132, or by writtenrequest. If you hold shares through a financial intermediary, you must purchase, redeem, and exchangeshares through your intermediary.

|         |   |
|--------------|--------|
| T.Rowe Price | 6      |

Tax Information

Any dividends or capital gainsare declared and paid annually, usually in December. Distributions by the fund, whether or not you reinvestthese amounts in additional fund shares, may be taxed as ordinary income or capital gains unless youinvest through a tax-deferred account. A redemption or exchange of fund shares may be taxable. 

Paymentsto Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the fund through abroker-dealer or other financial intermediary (such as a bank), the fund and its related companies maypay the intermediary for the sale of fund shares and related services. These payments may create a conflictof interest by influencing the broker-dealer or other intermediary and your salesperson to recommendthe fund over another investment. Ask your salesperson or visit your financial intermediary’s websitefor more information.

|                                                                  |           |
|-----------------------------------------------------------------------|----------------|
| T. Rowe PriceAssociates, Inc.100 East Pratt StreetBaltimore, MD 21202 | F149-0455/1/14 |