mfr.htm

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, including the fund’s statement of additional information, online at funds.mfs.com. You can also get this information at no cost by calling 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com. The fund’s prospectus and statement of additional information, both dated January 28, 2012, as may be supplemented from time to time, are incorporated by reference into this Summary Prospectus.

CLASS	TICKER SYMBOL
Class A	MFRFX
Class B	MFRBX
Class C	MFRCX
Class I	MRFIX
Class R1	MFRLX
Class R2	MSRRX
Class R3	MFRHX
Class R4	MFRJX
Class R5 (Formerly Class W)	MFRKX

This table describes the fees and expenses that you may pay when you buy and hold shares of the fund. Expenses have been adjusted to reflect current fee arrangements.

You may qualify for sales charge reductions if you and certain members of your family invest, or agree to invest in the future, at least $50,000 in MFS Funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers or Reductions” on page 7 of the fund’s prospectus and “Waivers of Sales Charges” on page I-14 of the fund’s statement of additional information Part I.

Share Class	A	B	C	I	ALL R
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	5.75%	None	None	None	None
Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, whichever is less)	1.00% #	4.00%	1.00%	None	None

Share Class	A	B	C	I	R1	R2	R3	R4	R5
Management Fee	0.43%	0.43%	0.43%	0.43%	0.43%	0.43%	0.43%	0.43%	0.43%
Distribution and/or Service (12b-1) Fees	0.25%	1.00%	1.00%	None	1.00%	0.50%	0.25%	None	None
Other Expenses	0.25%	0.25%	0.25%	0.25%	0.25%	0.25%	0.25%	0.25%	0.16%
Total Annual Fund Operating Expenses	0.93%	1.68%	1.68%	0.68%	1.68%	1.18%	0.93%	0.68%	0.59%

The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same.

	1 YEAR	3 YEARS	5 YEARS	10 YEARS
Class A Shares	$664	$854	$1,060	$1,652
Class B Shares assuming
redemption at end of period	$571	$830	$1,113	$1,788
no redemption at end of period	$171	$530	$913	$1,788
Class C Shares assuming
redemption at end of period	$271	$530	$913	$1,987
no redemption at end of period	$171	$530	$913	$1,987
Class I Shares	$69	$218	$379	$847
Class R1 Shares	$171	$530	$913	$1,987
Class R2 Shares	$120	$375	$649	$1,432
Class R3 Shares	$95	$296	$515	$1,143
Class R4 Shares	$69	$218	$379	$847
Class R5 Shares	$60	$189	$329	$738

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 shares are held in a taxable account. These transaction 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 69% of the average value of its portfolio.

MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in equity securities. Equity securities include common stocks, preferred stocks, securities convertible into stocks, and depositary receipts for those securities.

In selecting investments for the fund, MFS is not constrained to any particular investment style. MFS may invest the fund’s assets in the stocks of companies it believes to have above average earnings growth potential compared to other companies (growth companies), in the stocks of companies it believes are undervalued compared to their perceived worth (value companies), or in a combination of growth and value companies.

While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security. Derivatives include futures, forward contracts, options, structured securities, inverse floating rate instruments, and swaps.

A team of investment research analysts selects investments for the fund. MFS allocates the fund’s assets to analysts by broad market sectors.

MFS uses a bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual issuers. Quantitative models that systematically evaluate issuers may also be considered.

As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.

Stock Market/Company Risk: Stock markets are volatile and can decline significantly in response to issuer, market, economic, industry, political, regulatory, geopolitical, and other conditions, as well as to investor perceptions of these conditions. The price of an equity security can decrease significantly in response to these conditions, and these conditions can affect a single issuer or type of security, issuers within a broad market sector, industry or geographic region, or the market in general.

Foreign Risk: Exposure to foreign markets through issuers or currencies can involve additional risks relating to market, economic, political, regulatory, geopolitical, or other conditions. These factors can make foreign investments, especially those in emerging markets, more volatile and less liquid than U.S. investments. In addition, foreign markets can react differently to these conditions than the U.S. market.

Derivatives Risk: Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.

Leveraging Risk: Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses.

Investment Selection Risk: The MFS analysis of an investment can be incorrect and can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests.

Counterparty and Third Party Risk: Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability to perform in accordance with the terms of the transaction.

Liquidity Risk: It may not be possible to sell certain investments, types of investments, and/or segments of the market at any particular time or at an acceptable price.

The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.

The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at mfs.com or by calling 1-800-225-2606.

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MFS Research Fund

Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown.

The total return for the three-month period ended March 31, 2012 was 13.15%. During the period(s) shown in the bar chart, the highest quarterly return was 16.67% (for the calendar quarter ended September 30, 2009) and the lowest quarterly return was (22.89)% (for the calendar quarter ended December 31, 2008).

Share Class	1 YEAR	5 YEARS	10 YEARS
Returns Before Taxes
B Shares	(5.36)%	0.29%	2.71%
C Shares	(2.40)%	0.69%	2.56%
I Shares	(0.44)%	1.69%	3.58%
R1 Shares	(1.45)%	0.67%	2.46%
R2 Shares	(0.95)%	1.16%	2.94%
R3 Shares	(0.69)%	1.41%	3.24%
R4 Shares	(0.49)%	1.67%	3.52%
R5 Shares	(0.55)%	1.59%	3.48%
A Shares	(6.43)%	0.20%	2.64%
Returns After Taxes on Distributions A Shares	(6.55)%	0.08%	2.56%
Returns After Taxes on Distributions and Sale of Fund Shares A Shares	(4.03)%	0.15%	2.27%
Index Comparison (Reflects no deduction for fees, expenses or taxes)
Standard & Poor’s 500 Stock Index	2.11%	(0.25)%	2.92%

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. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.

You may purchase and redeem shares of the fund each day the New York Stock Exchange is open for trading. You may purchase or redeem shares either by having your financial intermediary process your purchase or redemption, or by overnight mail (MFS Service Center, Inc. (MFSC), c/o Boston Financial Data Services, 30 Dan Road, Canton, MA 02021-2809), by mail ([Fund Name], P.O. Box 55824, Boston, MA 02205-5824), by telephone (1-800-225-2606), or via the Internet at mfs.com (MFS Access).

Class	Initial Minimum	Subsequent Minimum
Class A, Class B, Class C	None – automatic investment plans and certain asset-based fee programs $25 – employer-sponsored retirement plans $250 – Traditional and Roth IRAs $1,000 – other accounts	$50 – by check and non-systematic written exchange request, and via MFSC telephone representatives None – other purchases
Class I, Class R1, Class R2, Class R3, Class R4, Class R5	None	None

If your shares are held in a taxable account, the fund’s distributions are taxable to you, and will be taxed as ordinary income and/or capital gains.

If you purchase shares of the fund through a broker/dealer or other financial intermediary (such as a bank), the fund, MFS, and MFS’ affiliates may pay the financial intermediary for the sale of shares of a fund and/or the servicing of shareholder accounts. These payments may create a conflict of interest by influencing your broker/dealer or other financial intermediary and your salesperson to recommend the fund over another investment. Ask your financial intermediary or visit your financial intermediary’s Web site for more information.

Portfolio Manager	Since	Title
Joseph G. MacDougall	2008	Investment Officer of MFS