summary.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 May 30, 2012, as may be supplemented from time to time, are incorporated by reference into this Summary Prospectus.

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 8 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)	4.75%	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	0.65%	0.65%	0.65%	0.65%	0.65%	0.65%	0.65%	0.65%	0.65%
Distribution and/or Service (12b-1) Fees	0.25%	1.00%	1.00%	None	1.00%	0.50%	0.25%	None	None
Other Expenses	0.23%	0.23%	0.23%	0.23%	0.23%	0.23%	0.23%	0.23%	0.15%
Total Annual Fund Operating Expenses	1.13%	1.88%	1.88%	0.88%	1.88%	1.38%	1.13%	0.88%	0.80%
Fee Reductions and/or Expense Reimbursements 1	(0.08)%	(0.08)%	(0.08)%	(0.08)%	(0.08)%	(0.08)%	(0.08)%	(0.08)%	(0.07)%
Total Annual Fund Operating Expenses After Fee Reductions and/or Expense Reimbursements	1.05%	1.80%	1.80%	0.80%	1.80%	1.30%	1.05%	0.80%	0.73%

#	On shares purchased without an initial sales charge and redeemed within 18 months of purchase for shares purchased on or after August 1, 2012, and within 24 months of purchase for shares purchased prior to August 1, 2012.

Massachusetts Financial Services Company has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity) such that "Total Annual Fund Operating Expenses" do not exceed 1.05% of the fund's average daily net assets annually for each of Class A and Class R3 shares, 1.80% of the fund's average daily net assets annually for each of Class B, Class C, and Class R1 shares, 0.80% of the fund's average daily net assets annually for each of Class I and Class R4 shares, 1.30% of the fund's average daily net assets annually for Class R2 shares, and 0.73% of the fund's average daily net assets annually for Class R5 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least May 31, 2013.

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	$577	$810	$1,060	$1,778
Class B Shares assuming
redemption at end of period	$583	$883	$1,209	$1,999
no redemption at end of period	$183	$583	$1,009	$1,999
Class C Shares assuming
redemption at end of period	$283	$583	$1,009	$2,194
no redemption at end of period	$183	$583	$1,009	$2,194
Class I Shares	$82	$273	$480	$1,077
Class R1 Shares	$183	$583	$1,009	$2,194
Class R2 Shares	$132	$429	$748	$1,650
Class R3 Shares	$107	$351	$615	$1,367
Class R4 Shares	$82	$273	$480	$1,077
Class R5 Shares	$75	$248	$437	$983

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 61% of the average value of its portfolio.

MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests directly and/or indirectly through investment in mutual funds advised by MFS at least 80% of the fund’s net assets in high income debt instruments.

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, to increase or decrease interest rate or currency exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, structured securities, inverse floating rate instruments, and swaps.

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 and instruments. Quantitative models that systematically evaluate issuers and instruments 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.

Interest Rate Risk: The price of a debt instrument falls when interest rates rise and rises when interest rates fall. Instruments with longer maturities, or that do not pay current interest, are more sensitive to interest rate changes.

Credit Risk: The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in the financial condition of the issuer, borrower, counterparty, or underlying collateral or assets, or changes in specific or general market, economic, industry, political, regulatory, geopolitical, or other conditions.

Lower quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Lower quality debt instruments are regarded as having predominantly speculative characteristics. Lower quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.

Foreign and Emerging Markets Risk: Exposure to foreign markets, especially emerging 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. Emerging markets can have less developed markets and less developed legal, regulatory, and accounting systems, and greater political, social, and economic instability than developed markets.

Currency Risk: The value of foreign currencies relative to the U.S. dollar fluctuates in response to market, economic, political, regulatory, geopolitical or other conditions, and a decline in the value of a foreign currency versus the U.S. dollar reduces the value in U.S. dollars of investments denominated in that foreign currency.

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.

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.

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MFS High Yield Opportunities Fund

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.

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 and one or more other measures of performance for markets in which the fund may invest.

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.

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 5.56%. During the period(s) shown in the bar chart, the highest quarterly return was 21.88% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (24.00)% (for the calendar quarter ended December 31, 2008).

Share Class	1 YEAR	5 YEARS	10 YEARS
Returns Before Taxes
B Shares	(1.30)%	3.58%	7.09%
C Shares	1.74%	3.90%	6.93%
I Shares	3.74%	4.89%	7.96%
R1 Shares	2.55%	3.85%	6.89%
R2 Shares	3.07%	4.37%	7.43%
R3 Shares	3.48%	4.65%	7.71%
R4 Shares	3.73%	4.92%	7.97%
R5 Shares	3.46%	4.78%	7.85%
A Shares	(1.44)%	3.60%	7.13%
Returns After Taxes on Distributions A Shares	(3.85)%	0.48%	3.88%
Returns After Taxes on Distributions and Sale of Fund Shares A Shares	(0.94)%	1.14%	4.11%
Index Comparisons (Reflects no deduction for fees, expenses or taxes)
Barclays Capital U.S. High-Yield Corporate Bond 2% Issuer Capped Index	4.96%	7.74%	8.96%
Barclays Capital U.S. High-Yield Corporate Bond Index	4.98%	7.54%	8.85%
BofA Merrill Lynch Global High Yield - Constrained Index	2.61%	7.26%	9.06%

Effective September 15, 2011, the Barclays Capital U.S. High-Yield Corporate Bond 2% Issuer Capped Index replaced the Barclays Capital U.S. High-Yield Corporate Bond Index because the adviser believes the Barclays Capital U.S. High-Yield Corporate Bond 2% Issuer Capped Index better reflects the fund’s investment strategies.

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 through MFS Service Center, Inc. (MFSC) by overnight mail, (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 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.

CLASS	TICKER SYMBOL
Class A	MHOAX
Class B	MHOBX
Class C	MHOCX
Class I	MHOIX
Class R1	MHORX
Class R2	MHOSX
Class R3	MHOTX
Class R4	MHOUX
Class R5 (Formerly Class W)	MHOVX

Portfolio Manager	Since	Title
David P. Cole	2006	Investment Officer of MFS
William J. Adams	2011	Investment Officer of MFS
Matthew W. Ryan	2005	Investment Officer of MFS