0001104659-12-070005.txt : 20121019 0001104659-12-070005.hdr.sgml : 20121019 20121019102226 ACCESSION NUMBER: 0001104659-12-070005 CONFORMED SUBMISSION TYPE: 485BPOS PUBLIC DOCUMENT COUNT: 8 FILED AS OF DATE: 20121019 DATE AS OF CHANGE: 20121019 EFFECTIVENESS DATE: 20121019 FILER: COMPANY DATA: COMPANY CONFORMED NAME: MFS SERIES TRUST X CENTRAL INDEX KEY: 0000783740 IRS NUMBER: 000000000 STATE OF INCORPORATION: MA FISCAL YEAR END: 1130 FILING VALUES: FORM TYPE: 485BPOS SEC ACT: 1933 Act SEC FILE NUMBER: 033-01657 FILM NUMBER: 121151644 BUSINESS ADDRESS: STREET 1: 500 BOYLSTON ST STREET 2: 15TH FL CITY: BOSTON STATE: MA ZIP: 02116 BUSINESS PHONE: 18006372929 MAIL ADDRESS: STREET 1: 500 BOYLSTON STREET STREET 2: 15TH FL CITY: BOSTON STATE: MA ZIP: 02116 FORMER COMPANY: FORMER CONFORMED NAME: MFS GOVERNMENT MORTGAGE FUND DATE OF NAME CHANGE: 19930408 FORMER COMPANY: FORMER CONFORMED NAME: MFS GOVERNMENT INCOME PLUS FUND DATE OF NAME CHANGE: 19930312 FORMER COMPANY: FORMER CONFORMED NAME: MASSACHUSETTS MFS GOVERNMENT INCOME PLUS FUND DATE OF NAME CHANGE: 19921015 FILER: COMPANY DATA: COMPANY CONFORMED NAME: MFS SERIES TRUST X CENTRAL INDEX KEY: 0000783740 IRS NUMBER: 000000000 STATE OF INCORPORATION: MA FISCAL YEAR END: 1130 FILING VALUES: FORM TYPE: 485BPOS SEC ACT: 1940 Act SEC FILE NUMBER: 811-04492 FILM NUMBER: 121151645 BUSINESS ADDRESS: STREET 1: 500 BOYLSTON ST STREET 2: 15TH FL CITY: BOSTON STATE: MA ZIP: 02116 BUSINESS PHONE: 18006372929 MAIL ADDRESS: STREET 1: 500 BOYLSTON STREET STREET 2: 15TH FL CITY: BOSTON STATE: MA ZIP: 02116 FORMER COMPANY: FORMER CONFORMED NAME: MFS GOVERNMENT MORTGAGE FUND DATE OF NAME CHANGE: 19930408 FORMER COMPANY: FORMER CONFORMED NAME: MFS GOVERNMENT INCOME PLUS FUND DATE OF NAME CHANGE: 19930312 FORMER COMPANY: FORMER CONFORMED NAME: MASSACHUSETTS MFS GOVERNMENT INCOME PLUS FUND DATE OF NAME CHANGE: 19921015

0000783740 S000002506 MFS Aggressive Growth Allocation Fund

C000006838 A MAAGX

C000006839 R4 MAALX

C000006840 529A EAGTX

C000006841 529B EBAAX

C000006842 529C ECAAX

C000006843 B MBAGX

C000006844 C MCAGX

C000006845 I MIAGX

C000006847 R1 MAAFX

C000006849 R2 MAWAX

C000006850 R3 MAAHX

0000783740 S000002507 MFS Moderate Allocation Fund

C000006851 A MAMAX

C000006852 R4 MAMJX

C000006853 529A EAMDX

C000006854 529B EBMDX

C000006855 529C ECMAX

C000006856 B MMABX

C000006857 C MMACX

C000006858 I MMAIX

C000006860 R1 MAMFX

C000006862 R2 MARRX

C000006863 R3 MAMHX

0000783740 S000002510 MFS Conservative Allocation Fund

C000006887 A MACFX

C000006888 R4 MACJX

C000006889 529A ECLAX

C000006890 529B EBCAX

C000006891 529C ECACX

C000006892 B MACBX

C000006893 C MACVX

C000006894 I MACIX

C000006896 R1 MACKX

C000006898 R2 MCARX

C000006899 R3 MACNX

0000783740 S000002512 MFS Emerging Markets Equity Fund

C000006904 A MEMAX

C000006905 B MEMBX

C000006906 C MEMCX

C000006907 I MEMIX

C000071424 CLASS R1 MEMRX

C000071425 CLASS R2 MEMFX

C000071426 CLASS R3 MEMGX

C000071427 CLASS R4 MEMHX

C000071428 CLASS R5 MEMJX

0000783740 S000002514 MFS Growth Allocation Fund

C000006911 A MAGWX

C000006912 R4 MAGJX

C000006913 529A EAGWX

C000006914 529B EBGWX

C000006915 529C ECGWX

C000006916 B MBGWX

C000006917 C MCGWX

C000006918 I MGWIX

C000006920 R1 MAGMX

C000006922 R2 MGALX

C000006923 R3 MAGEX

0000783740 S000002515 MFS International Diversification Fund

C000006924 A MDIDX

C000006925 R4 MDITX

C000006926 529A MDIEX

C000006927 529B MDIMX

C000006928 529C MDINX

C000006929 B MDIFX

C000006930 C MDIGX

C000006931 I MDIJX

C000006933 R1 MDIOX

C000006935 R2 MDIKX

C000006936 R3 MDIHX

0000783740 S000002516 MFS International Growth Fund

C000006937 A MGRAX

C000006938 B MGRBX

C000006939 C MGRCX

C000006940 I MQGIX

C000034484 Class R5 MGRDX

C000071430 CLASS R4 MGRVX

C000071431 CLASS R1 MGRRX

C000071432 CLASS R2 MGRQX

C000071433 CLASS R3 MGRTX

0000783740 S000002517 MFS International Value Fund

C000006941 A MGIAX

C000006942 B MGIBX

C000006943 C MGICX

C000006944 I MINIX

C000034485 Class R5 MINJX

C000071434 CLASS R1 MINRX

C000071435 CLASS R2 MINFX

C000071436 CLASS R3 MINGX

C000071437 CLASS R4 MINHX

0000783740 S000028956 MFS GLOBAL BOND FUND

C000088935 A MGBAX

C000088936 B MGBBX

C000088937 C MGBDX

C000088938 I MGBJX

C000088939 R1 MGBKX

C000088940 R2 MGBLX

C000088941 R3 MGBMX

C000088942 R4 MGBNX

C000120923 R5 MGBOX

0000783740 S000031672 MFS Absolute Return Fund

C000098544 A MRNAX

C000098545 B MRNBX

C000098546 C MRNCX

C000098547 I MRNIX

C000098548 R1 MRNRX

C000098549 R2 MRNSX

C000098550 R3 MRNTX

C000098551 R4 MRNUX

C000120924 R5 MRNVX

485BPOS 1 a12-20412_14485bpos.htm POST-EFFECTIVE AMENDMENT FILED PURSUANT TO SECURITIES ACT RULE 485(B)

As filed with the Securities and Exchange Commission on October 19, 2012

	1933 Act File No. 33-1657
	1940 Act File No. 811-4492

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER THE SECURITIES ACT OF 1933

POST-EFFECTIVE AMENDMENT NO. 88

AND

REGISTRATION STATEMENT

UNDER THE INVESTMENT COMPANY ACT OF 1940

AMENDMENT NO. 87

MFS® SERIES TRUST X

(Exact Name of Registrant as Specified in Charter)

500 Boylston Street, Boston, Massachusetts 02116

(Address of Principal Executive Offices)

Registrant’s Telephone Number, including Area Code: 617-954-5000

Susan S. Newton Massachusetts Financial Services Company,

500 Boylston Street, Boston, MA 02116

(Name and Address of Agent for Service)

APPROXIMATE DATE OF PROPOSED PUBLIC OFFERING:

It is proposed that this filing will become effective (check appropriate box)

x immediately upon filing pursuant to paragraph (b)

o on [date] pursuant to paragraph (b)

o 60 days after filing pursuant to paragraph (a)(i)

o on [date] pursuant to paragraph (a)(i)

o 75 days after filing pursuant to paragraph (a)(ii)

o on [date] pursuant to paragraph (a)(ii) of rule 485

If appropriate, check the following box:

o this post-effective amendment designates a new effective date for a previously filed post-effective amendment

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Post-Effective Amendment to the Registration Statement to be signed on its behalf by the undersigned, thereto duly authorized, in the City of Boston and The Commonwealth of Massachusetts on the 19th day of October, 2012

	MFS® SERIES TRUST X


	By:	JOHN M. CORCORAN*
	Name:	John M. Corcoran
	Title:	President

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment to its Registration Statement has been signed below by the following persons in the capacities indicated on October 19, 2012.

SIGNATURE		TITLE


JOHN M. CORCORAN*		President (Principal Executive Officer)
John M. Corcoran


DAVID L. DILORENZO*		Principal Financial and Accounting Officer
David L. DiLorenzo


ROBERT E. BUTLER*		Trustee
Robert E. Butler


MAUREEN R. GOLDFARB*		Trustee
Maureen R. Goldfarb


DAVID H. GUNNING*		Trustee
David H. Gunning

WILLIAM R. GUTOW*	Trustee
William R. Gutow


MICHAEL HEGARTY*	Trustee
Michael Hegarty


JOHN P. KAVANAUGH*	Trustee
John P. Kavanaugh


ROBERT J. MANNING*	Trustee
Robert J. Manning


J. DALE SHERRATT*	Trustee
J. Dale Sherratt


LAURIE J. THOMSEN*	Trustee
Laurie J. Thomsen


ROBERT W. UEK*	Trustee
Robert W. Uek

		*By:	SUSAN S. NEWTON
		Name:	Susan S. Newton
			as Attorney-in-fact

		Executed by Susan S. Newton on behalf of those indicated pursuant to a Power of Attorney, dated September 11, 2012 (Trustees), and a Power of Attorney, dated September 11, 2012 (Corcoran) (DiLorenzo); filed herewith.

MFS Series Trust I

MFS Series Trust II

MFS Series Trust III

MFS Series Trust IV

MFS Series Trust V

MFS Series Trust VI

MFS Series Trust VII

MFS Series Trust VIII

MFS Series Trust IX

MFS Series Trust X

MFS Series Trust XI

MFS Series Trust XII

MFS Series Trust XIII

MFS Series Trust XIV

MFS Series Trust XV

MFS Series Trust XVI

Massachusetts Investors Growth Stock Fund

Massachusetts Investors Trust

MFS Institutional Trust

MFS Municipal Series Trust

MFS Variable Insurance Trust

MFS Variable Insurance Trust II

MFS California Municipal Fund

MFS Charter Income Trust

MFS Government Markets Income Trust

MFS High Income Municipal Trust

MFS High Yield Municipal Trust

MFS InterMarket Income Trust I

MFS Intermediate High Income Fund

MFS Intermediate Income Trust

MFS Investment Grade Municipal Trust

MFS Multimarket Income Trust

MFS Municipal Income Trust

MFS Special Value Trust

(each a “Registrant”)

POWER OF ATTORNEY

The undersigned, a Trustee of each of the above-mentioned Registrants, hereby severally constitutes and appoints Mark N. Polebaum, Susan S. Newton, Christopher R. Bohane, Thomas H. Connors, Brian E. Langenfeld and Susan A. Pereira, and each of them singly, as true and lawful attorneys, with full power to them and each of them to sign for each of the undersigned, in the names of, and in the capacities indicated below, any

Registration Statement and any and all amendments thereto and to file the same with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission for the purpose of registering the Registrant as a management investment company under the Investment Company Act of 1940 and/or the shares issued by the Registrant under the Securities Act of 1933 granting unto my said attorneys, and each of them, acting alone, full power and authority to do and perform each and every act and thing requisite or necessary or desirable to be done in the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys or any of them may lawfully do or cause to be done by virtue thereof.

IN WITNESS WHEREOF, the undersigned have hereunto set their hand on this 11th day of September, 2012.

ROBERT E. BUTLER		Trustee
Robert E. Butler


MAUREEN R. GOLDFARB		Trustee
Maureen R. Goldfarb


DAVID H. GUNNING		Trustee
David H. Gunning


WILLIAM R. GUTOW		Trustee
William R. Gutow


MICHAEL HEGARTY		Trustee
Michael Hegarty


JOHN P. KAVANAUGH		Trustee
John P. Kavanaugh


ROBERT J. MANNING		Trustee
Robert J. Manning


J. DALE SHERRATT		Trustee
J. Dale Sherratt

LAURIE J. THOMSEN		Trustee
Laurie J. Thomsen


ROBERT W. UEK		Trustee
Robert W. Uek

MFS Series Trust I

MFS Series Trust II

MFS Series Trust III

MFS Series Trust IV

MFS Series Trust V

MFS Series Trust VI

MFS Series Trust VII

MFS Series Trust VIII

MFS Series Trust IX

MFS Series Trust X

MFS Series Trust XI

MFS Series Trust XII

MFS Series Trust XIII

MFS Series Trust XIV

MFS Series Trust XV

MFS Series Trust XVI

Massachusetts Investors Growth Stock Fund

Massachusetts Investors Trust

MFS Institutional Trust

MFS Municipal Series Trust

MFS Variable Insurance Trust

MFS Variable Insurance Trust II

MFS California Municipal Fund

MFS Charter Income Trust

MFS Government Markets Income Trust

MFS High Income Municipal Trust

MFS High Yield Municipal Trust

MFS InterMarket Income Trust I

MFS Intermediate High Income Fund

MFS Intermediate Income Trust

MFS Investment Grade Municipal Trust

MFS Multimarket Income Trust

MFS Municipal Income Trust

MFS Special Value Trust

(each a “Registrant”)

POWER OF ATTORNEY

The undersigned, being the President and Principal Executive Officer, and Treasurer and Principal Financial and Accounting Officer, respectively, of each of the above-mentioned Registrants, hereby severally constitutes and appoints Mark N. Polebaum, Susan S. Newton, Christopher R. Bohane, Thomas H. Connors, Brian E. Langenfeld and Susan A. Pereira, and each of them singly, as true and lawful attorneys, with full power to them and each of them to sign for each of the undersigned, in the names of, and in the capacities indicated below, any Registration Statement and any and all amendments thereto and to file the same with all exhibits thereto, and other documents in connection therewith, with the Securities and

Exchange Commission for the purpose of registering the Registrant as a management investment company under the Investment Company Act of 1940 and/or the shares issued by the Registrant under the Securities Act of 1933 granting unto my said attorneys, and each of them, acting alone, full power and authority to do and perform each and every act and thing requisite or necessary or desirable to be done in the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys or any of them may lawfully do or cause to be done by virtue thereof.

IN WITNESS WHEREOF, the undersigned have hereunto set their hand on this 11th day of September, 2012.

JOHN M. CORCORAN		President (Principal Executive Officer)
John M. Corcoran


DAVID L. DILORENZO		Principal Financial and Accounting Officer
David L. DiLorenzo

MFS SERIES TRUST X

MFS® ABSOLUTE RETURN FUND

MFS® AGGRESSIVE GROWTH ALLOCATION FUND

MFS® CONSERVATIVE ALLOCATION FUND

MFS® EMERGING MARKETS EQUITY FUND

MFS® GLOBAL BOND FUND

MFS® GROWTH ALLOCATION FUND

MFS® INTERNATIONAL DIVERSIFICATION FUND

MFS® INTERNATIONAL GROWTH FUND

MFS® INTERNATIONAL VALUE FUND

MFS® MODERATE ALLOCATION FUND

INDEX TO EXHIBITS

EXHIBIT NO.	DESCRIPTION OF EXHIBIT	PAGE NO.

101	Risk/Return summary of each fund’s prospectus as an Interactive Data File using eXtensible Business Reporting Language (“XBRL”)

EX-101.INS 2 ck0000783740-20120531.xml XBRL INSTANCE DOCUMENT 485BPOS 2012-05-31 0000783740 2012-09-28 MFS SERIES TRUST X false 2012-09-27 2012-09-28 <tt>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 10% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000031672Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The fund's investment objective is to seek total return.</tt> <tt>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 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.</tt> <tt>In managing the fund, MFS (Massachusetts Financial Services Company, the fund's investment adviser) employs an absolute return investment approach, which means the fund seeks to earn a positive return regardless of market conditions. As a result, if this strategy is successful, it is expected that the fund will outperform the general equity market during periods of flat or negative market performance, will underperform during periods of strong positive market performance, and will typically produce less volatile returns than the general equity market.    MFS seeks to achieve the fund's objective by generating returns from a combination of (1) individual security selection of primarily debt instruments and (2) a tactical asset allocation overlay primarily using derivative instruments to manage the fund's exposure to asset classes, markets and currencies. Derivatives include futures, forward contracts, options, structured securities, inverse floating rate instruments, and swaps. The fund's performance may not be correlated with the performance of the asset classes, markets or currencies represented by the individual investments selected by MFS.    Individual Security Selection:  In selecting direct investments for the fund, MFS normally invests the fund's assets primarily in debt instruments.    Debt instruments include corporate bonds, U.S. Government securities, asset-backed securities, municipal instruments, foreign government securities, inflation-adjusted bonds, and other obligations to repay money borrowed.    Of the fund's investments in debt instruments, MFS generally invests substantially all of these investments in investment grade debt instruments.    While MFS may invest the fund's assets in debt instruments of any effective maturity, MFS generally focuses on short and intermediate term debt instruments.    MFS may invest the fund's assets in U.S. and foreign securities, including emerging market securities.    While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives as part of its individual security selection process, 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. 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 instruments and their issuers. Quantitative models that systematically evaluate instruments may also be considered.    Tactical Asset Allocation Overlay:  MFS employs a top-down tactical asset allocation process to adjust the fund's exposure to asset classes, markets and currencies based on its assessment of the relative attractiveness of such asset classes, markets and currencies. MFS manages the fund's exposure to asset classes, markets and currencies primarily through the use of derivative instruments based on its proprietary quantitative models.    In managing the tactical overlay, MFS may increase or decrease the fund's exposure to asset classes, markets and/or currencies resulting from MFS' individual security selection based on MFS' assessment of the risk/return potential of such asset classes, markets and/or currencies. MFS may also expose the fund to asset classes, markets and/or currencies in which its individual security selection has resulted in no or little exposure (e.g., commodity-related investments, real estate-related investments, equity securities, inflation-adjusted debt instruments). After taking into account the tactical overlay, the fund's exposure to certain asset classes in which its individual security selection has resulted in no or little exposure will normally fall within the following ranges:    Asset Class                           Range   U.S. and foreign equity securities      ±15% Inflation-adjusted debt instruments     ±10% Commodity-related investments           ±10% Real estate-related investments         ± 5%    After taking into account the tactical overlay, the fund's exposure to the less than investment grade quality debt instrument (lower quality debt instrument) and long term debt instrument asset classes may at times be significant, and the fund may have significant exposure to issuers in a single country, a small number of countries, or a particular geographic region. MFS may adjust the fund's net exposure to asset classes, markets and/or currencies by taking net short positions in an asset class, market or currency if MFS believes the risk/return potential of such asset class, market or currency is unattractive.  Alternatively, MFS may cause the fund to take net long positions in an asset class, market or currency if MFS believes such asset class, market or currency appears attractive. MFS may also use derivatives to seek to limit the fund's exposure to certain extreme market events.    MFS' tactical allocation process for the fund will typically make extensive use of derivatives.</tt> Summary of Key Information 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. Example The annual fund operating expenses for Class R5 shares are based on estimated "Other Expenses" for the current fiscal year expressed as a percentage of the fund's estimated average net assets during the period. The bar chart and performance table are not included because the fund has not had a full calendar year of operations. Investment Objective As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.10 Performance Information 50000 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Portfolio Turnover <tt>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.    The principal risks of investing in the fund are:    Investment Selection and Allocation Risk:  MFS' investment analysis, its selection of investments, its assessment of the risk/return potential of asset classes, markets and currencies, and its adjustments to the fund's exposure to asset classes, markets, and currencies through the use of derivatives may not produce the intended results and/or 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.    Investment Strategy Risk:  The fund's strategy to manage its exposure to asset classes, markets, and currencies may not produce the intended results. In addition, the strategies MFS may implement to limit the fund's exposure to certain extreme market events may not work as intended, and the costs associated with such strategies will reduce the fund's returns. 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.    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.    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.    Geographic Concentration Risk:  The fund's performance could be closely tied to the market, currency, economic, political, regulatory, geopolitical, or other conditions in the countries or regions in which the fund invests and could be more volatile than the performance of more geographically-diversified funds. Prepayment/Extension Risk:  Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument's holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended.    Inflation-Adjusted Debt Instruments Risk:  Interest payments on inflation-adjusted debt instruments can be unpredictable and vary based on the level of inflation. If inflation is negative, principal and income can both decline. Municipal Risk:  The price of a municipal instrument can be volatile and significantly affected by adverse tax or court rulings, legislative or political changes, changes in specific or general market and economic conditions, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in these industries can significantly affect the fund and the overall municipal market. 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.    Commodity Risk:  The value of commodities may be more volatile than the value of equity securities or debt instruments and their value may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity. The price of a commodity may be affected by demand/supply imbalances in the market for the commodity.    Tax Risk:  In order to qualify as a regulated investment company (RIC) under the Internal Revenue Code of 1986, as amended, the fund must meet certain requirements regarding the source of its income, the diversification of its assets, and the distribution of its income. If the fund were to fail to qualify as a RIC and became subject to federal income tax, shareholders of the fund would be subject to the risk of diminished returns.    Real Estate-Related Investment Risk:  The risks of investing in real estate-related securities include certain risks associated with the direct ownership of real estate and the real estate industry in general. These include risks related to general, regional and local economic conditions; fluctuations in interest rates; property tax rates, zoning laws, environmental regulations and other governmental action; cash flow dependency; increased operating expenses; lack of availability of mortgage funds; losses due to natural disasters; overbuilding; losses due to casualty or condemnation; changes in property values and rental rates; and other factors.  The securities of smaller real estate-related issuers can be more volatile and less liquid than securities of larger issuers and their issuers can have more limited financial resources. Leveraging Risk:  Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses.    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.</tt> Fees and Expenses Principal Investment Strategies <tt>The bar chart and performance table are not included because the fund has not had a full calendar year of operations.</tt> <tt>This table describes the fees and expenses that you may pay when you buy and hold shares of the fund. Expenses for Class A, Class B, Class C, Class I, Class R1, Class R2, Class R3, and Class R4 shares have been adjusted to reflect current fee arrangements. The annual fund operating expenses for Class R5 shares are based on estimated "Other Expenses" for the current fiscal year expressed as a percentage of the fund's estimated average net assets during the period.    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 11 of the fund's prospectus and "Waivers of Sales Charges" on page I-14 of the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000031672Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000031672Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000031672Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> MRNVX 0.0000 91 369 -0.0040 1521 <tt>R5</tt> 669 0.0064 0.0065 2013-09-30 0.0000 0.0089 0.0129 <tt>Class R5 Shares</tt> <tt>ALL R</tt> 0.0000 MRNUX 0.0000 91 369 -0.0040 1521 <tt>R4</tt> 669 0.0064 0.0065 2013-09-30 0.0000 0.0089 0.0129 <tt>Class R4 Shares</tt> <tt>ALL R</tt> 0.0000 MRNTX 0.0000 116 447 -0.0040 1801 <tt>R3</tt> 802 0.0064 0.0065 2013-09-30 0.0025 0.0114 0.0154 <tt>Class R3 Shares</tt> <tt>ALL R</tt> 0.0000 MRNSX 0.0000 142 524 -0.0040 2072 <tt>R2</tt> 932 0.0064 0.0065 2013-09-30 0.0050 0.0139 0.0179 <tt>Class R2 Shares</tt> <tt>ALL R</tt> 0.0000 MRNRX 0.0000 192 677 -0.0040 2595 <tt>R1</tt> 1189 0.0064 0.0065 2013-09-30 0.0100 0.0189 0.0229 <tt>Class R1 Shares</tt> <tt>ALL R</tt> 0.0000 MRNIX 0.0000 91 369 -0.0040 1521 <tt>I</tt> 669 0.0064 0.0065 2013-09-30 0.0000 0.0089 0.0129 <tt>Class I Shares</tt> <tt>I</tt> 0.0000 MRNCX 0.0000 292 192 677 -0.0040 2595 <tt>C</tt> 1189 0.0064 0.0065 2013-09-30 2595 677 1189 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0189 0.0229 <tt>Class C Shares assuming redemption at end of period</tt> <tt>C</tt> 0.0100 MRNBX 0.0000 592 192 977 -0.0040 2406 <tt>B</tt> 1389 0.0064 0.0065 2013-09-30 2406 677 1189 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0189 0.0229 <tt>Class B Shares assuming redemption at end of period</tt> <tt>B</tt> 0.0400 MRNAX 0.0475 586 901 -0.0040 2190 <tt>A</tt> 1239 0.0064 0.0065 2013-09-30 0.0025 0.0114 0.0154 <tt>Class A Shares</tt> <tt>A</tt> 0.0100 Because MFS may invest a relatively large percentage of the fund's assets in a single issuer or small number of issuers, the fund's performance could be closely tied to the value of that one issuer or issuers, and could be more volatile than the performance of diversified funds. <tt>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 98% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000028956Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000028956Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The fund's investment objective is to seek total return with an emphasis on current income, but also considering capital appreciation.</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests at least 80% of the fund's net assets in debt instruments of U.S. and foreign issuers, including emerging markets issuers.    While MFS may invest the fund's assets in debt instruments of any type, MFS generally focuses on debt instruments of U.S. and foreign governments.    MFS may invest up to 100% of the fund's assets in less than investment grade quality debt instruments (lower quality debt instruments). MFS may invest a large percentage of the fund's assets in issuers in a single country, a small number of countries, or a particular geographic region.    MFS may invest up to 35% of the fund's assets in any industry that accounts for more than 20% of the global bond market. The fund is a non-diversified fund. This means that MFS may invest a relatively large percentage of the fund's assets in a single issuer or a small number of issuers.    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 generally uses a top-down approach to buying and selling investments for the fund. MFS allocates the fund's assets across countries and selects investments primarily based on fundamental economic and financial analysis. Quantitative models that systematically evaluate economic and financial factors may also be considered. MFS may also use a bottom-up investment approach, particularly for corporate debt instruments, selecting investments based on fundamental analysis of individual instruments and their issuers.</tt> Summary of Key Information 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. Example 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. The annual fund operating expenses for Class R5 shares are based on estimated "Other Expenses" for the current fiscal year expressed as a percentage of the fund's estimated average net assets during the period. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.98 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. 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. Performance Information 50000 <tt>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.</tt> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing how the fund's performance over time compares with that of a broad measure of market performance. <tt>The total return for the six-month period ended June 30, 2012 was 0.53%. During the period(s) shown in the bar chart, the highest quarterly return was 3.87% (for the calendar quarter ended June 30, 2011) and the lowest quarterly return was (0.07)% (for the calendar quarter ended March 31, 2011).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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.    The principal risks of investing in the fund are:    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.    Prepayment/Extension Risk:  Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument's holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended.    Inflation-Adjusted Debt Instruments Risk:  Interest payments on inflation-adjusted debt instruments can be unpredictable and vary based on the level of inflation. If inflation is negative, principal and income can both decline. Geographic Concentration Risk:  The fund's performance could be closely tied to the market, currency, economic, political, regulatory, geopolitical, or other conditions in the countries or regions in which the fund invests and could be more volatile than the performance of more geographically-diversified funds.    Non-Diversification Risk:  Because MFS may invest a relatively large percentage of the fund's assets in a single issuer or small number of issuers, the fund's performance could be closely tied to the value of that one issuer or issuers, and could be more volatile than the performance of diversified funds. 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.    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.    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.    Investment Selection Risk:  MFS' investment analysis and its selection of investments may not produce the intended results and/or 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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing 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.</tt> <tt>This table describes the fees and expenses that you may pay when you buy and hold shares of the fund. Expenses for Class A, Class B, Class C, Class I, Class R1, Class R2, Class R3, and Class R4 shares have been adjusted to reflect current fee arrangements. The annual fund operating expenses for Class R5 shares are based on estimated "Other Expenses" for the current fiscal year expressed as a percentage of the fund's estimated average net assets during the period.    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 9 of the fund's prospectus and "Waivers of Sales Charges" on page I-14 of the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000028956Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000028956Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000028956Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000028956Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparison (Reflects no deduction for fees, expenses or taxes) JPMorgan Global Government Bond Index (Unhedged) 0.0722 0.0981 2010-06-02 A Shares Returns After Taxes on Distributions and Sale of Fund Shares 0.0066 0.0335 2010-06-02 A Shares Returns After Taxes on Distributions -0.0115 0.0332 2010-06-02 MGBOX 0.0000 R5 Shares Returns Before Taxes 86 270 -0.0001 1048 <tt>R5</tt> 470 0.0568 0.0025 0.0060 2013-09-30 0.0000 0.0084 0.0085 <tt>Class R5 Shares </tt> 0.0829 2010-06-02 <tt>ALL R </tt> 0.0000 MGBNX 0.0000 R4 Shares Returns Before Taxes 86 270 -0.0001 1048 <tt>R4</tt> 470 0.0579 0.0025 0.0060 2013-09-30 0.0000 0.0084 0.0085 <tt>Class R4 Shares</tt> 0.0830 2010-06-02 <tt>ALL R </tt> 0.0000 MGBMX 0.0000 R3 Shares Returns Before Taxes 111 349 -0.0001 1339 <tt>R3</tt> 605 0.0542 0.0025 0.0060 2013-09-30 0.0025 0.0109 0.0110 <tt>Class R3 Shares</tt> 0.0798 2010-06-02 <tt>ALL R </tt> 0.0000 MGBLX 0.0000 R2 Shares Returns Before Taxes 136 427 -0.0001 1623 <tt>R2</tt> 738 0.0516 0.0025 0.0060 2013-09-30 0.0050 0.0134 0.0135 <tt>Class R2 Shares</tt> 0.0773 2010-06-02 <tt>ALL R </tt> 0.0000 MGBKX 0.0000 R1 Shares Returns Before Taxes 187 581 -0.0001 2168 <tt>R1</tt> 1000 0.0474 0.0025 0.0060 2013-09-30 0.0100 0.0184 0.0185 <tt>Class R1 Shares</tt> 0.0722 2010-06-02 <tt>ALL R </tt> 0.0000 MGBJX 0.0000 I Shares Returns Before Taxes 86 270 -0.0001 1048 <tt>I</tt> 470 0.0568 0.0025 0.0060 2013-09-30 0.0000 0.0084 0.0085 <tt>Class I Shares</tt> 0.0829 2010-06-02 <tt>I</tt> 0.0000 MGBDX 0.0000 C Shares Returns Before Taxes 287 187 581 -0.0001 2168 <tt>C</tt> 1000 0.0385 0.0025 0.0060 2013-09-30 2168 581 1000 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0184 0.0185 <tt>Class C Shares assuming redemption at end of period</tt> 0.0722 2010-06-02 <tt>C</tt> 0.0100 MGBBX 0.0000 B Shares Returns Before Taxes 587 187 881 -0.0001 1972 <tt>B</tt> 1200 0.0078 0.0025 0.0060 2013-09-30 1972 581 1000 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0184 0.0185 <tt>Class B Shares assuming redemption at end of period</tt> 0.0478 2010-06-02 <tt>B</tt> 0.0400 MGBAX the lowest quarterly return the highest quarterly return 0.0475 2012-06-30 A Shares Returns Before Taxes 581 2011-06-30 807 -0.0007 -0.0001 1751 <tt>A</tt> 1051 0.0387 0.0097 0.0025 0.0060 2013-09-30 2011-03-31 The total return for the six-month period ended 0.0601 0.0025 0.0109 0.0110 <tt>Class A Shares</tt> 0.0514 2010-06-02 0.0053 <tt>A</tt> 0.0100 <tt>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 15% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002517Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002517Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The fund's investment objective is to seek capital appreciation.</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund's assets primarily in foreign equity securities, including emerging market equity securities. Equity securities include common stocks, preferred stocks, securities convertible into stocks, and depositary receipts for those securities. MFS may invest a large percentage of the fund's assets in issuers in a single country, a small number of countries, or a particular geographic region.    MFS focuses on investing the fund's assets in the stocks of companies it believes are undervalued compared to their perceived worth (value companies).    MFS may invest the fund's assets in companies of any size.    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.</tt> Summary of Key Information 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. Example 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. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.15 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. 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. Performance Information 50000 <tt>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.</tt> 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. <tt>The total return for the six-month period ended June 30, 2012 was 6.11%. During the period(s) shown in the bar chart, the highest quarterly return was 22.56% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (16.30)% (for the calendar quarter ended September 30, 2008).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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.    The principal risks of investing in the fund are:    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.    Value Company Risk:  The stocks of value companies can continue to be undervalued for long periods of time and not realize their expected value and can be more volatile than the market in general.    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.    Geographic Concentration Risk:  The fund's performance could be closely tied to the market, currency, economic, political, regulatory, geopolitical, or other conditions in the countries or regions in which the fund invests and could be more volatile than the performance of more geographically-diversified funds.    Investment Selection Risk:  MFS' investment analysis and its selection of investments may not produce the intended results and/or 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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>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.</tt> <tt>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-15 of the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002517Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002517Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000002517Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002517Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparisons (Reflects no deduction for fees, expenses or taxes) MSCI EAFE (Europe, Australasia, Far East) Index (gross div) -0.1173 -0.0426 0.0512 Index Comparisons (Reflects no deduction for fees, expenses or taxes) MSCI EAFE (Europe, Australasia, Far East) Value Index (gross div) -0.1165 -0.0577 0.0553 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.0455 -0.0147 0.0662 A Shares Returns After Taxes on Distributions -0.0768 -0.0231 0.0691 MINHX 0.0000 R4 Shares Returns Before Taxes 98 306 1178 <tt>R4</tt> 531 -0.0172 0.0018 0.0078 -0.0027 0.0000 0.0868 0.0096 <tt>Class R4 Shares</tt> <tt>ALL R </tt> 0.0000 MINGX 0.0000 R3 Shares Returns Before Taxes 123 384 1466 <tt>R3</tt> 665 -0.0192 0.0018 0.0078 -0.0050 0.0025 0.0841 0.0121 <tt>Class R3 Shares</tt> <tt>ALL R </tt> 0.0000 MINFX 0.0000 R2 Shares Returns Before Taxes 149 462 1746 <tt>R2</tt> 797 -0.0218 0.0018 0.0078 -0.0076 0.0050 0.0814 0.0146 <tt>Class R2 Shares</tt> <tt>ALL R </tt> 0.0000 MINRX 0.0000 R1 Shares Returns Before Taxes 199 615 2285 <tt>R1</tt> 1057 -0.0270 0.0018 0.0078 -0.0125 0.0100 0.0760 0.0196 <tt>Class R1 Shares</tt> <tt>ALL R </tt> 0.0000 MINJX 0.0000 R5 Shares Returns Before Taxes 88 274 1061 <tt>R5</tt> 477 -0.0181 0.0008 0.0078 -0.0034 0.0000 0.0858 0.0086 <tt>Class R5 Shares</tt> <tt>ALL R </tt> 0.0000 MINIX 0.0000 I Shares Returns Before Taxes 98 306 1178 <tt>I</tt> 531 -0.0169 0.0018 0.0078 -0.0025 0.0000 0.0869 0.0096 <tt>Class I Shares</tt> <tt>I</tt> 0.0000 MGICX 0.0000 C Shares Returns Before Taxes 299 199 615 2285 <tt>C</tt> 1057 -0.0363 0.0018 0.0078 2285 -0.0125 615 1057 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0760 0.0196 <tt>Class C Shares assuming redemption at end of period</tt> <tt>C</tt> 0.0100 MGIBX 0.0000 B Shares Returns Before Taxes 599 199 915 2091 <tt>B</tt> 1257 -0.0654 0.0018 0.0078 2091 -0.0158 615 1057 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0775 0.0196 <tt>Class B Shares assuming redemption at end of period</tt> <tt>B</tt> 0.0400 MGIAX -0.0695 lowest quarterly return the highest quarterly return 0.0575 2012-06-30 A Shares Returns Before Taxes 691 2009-06-30 937 -0.1630 0.2677 0.0913 1957 <tt>A</tt> 1202 0.0715 0.2256 -0.0760 0.0018 -0.3191 0.0078 2008-09-30 0.2464 -0.0172 0.1425 The total return for the six-month period ended -0.0196 0.3203 0.0025 0.0765 0.0121 0.2808 <tt>Class A Shares</tt> 0.0611 <tt>A</tt> 0.0100 <tt>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 39% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002516Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002516Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The fund's investment objective is to seek capital appreciation.</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund's assets primarily in foreign equity securities, including emerging market equity securities. Equity securities include common stocks, preferred stocks, securities convertible into stocks, and depositary receipts for those securities. MFS may invest a large percentage of the fund's assets in issuers in a single country, a small number of countries, or a particular geographic region. MFS focuses on investing the fund's assets in the stocks of companies it believes to have above average earnings growth potential compared to other companies (growth companies).    MFS may invest the fund's assets in companies of any size.    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.</tt> Summary of Key Information 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. Example 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. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.39 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. 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. Performance Information 50000 <tt>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.</tt> 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. <tt>The total return for the six-month period ended June 30, 2012 was 6.25%. During the period(s) shown in the bar chart, the highest quarterly return was 23.27% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (19.64)% (for the calendar quarter ended September 30, 2011).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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.    The principal risks of investing in the fund are:    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 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. Geographic Concentration Risk: The fund's performance could be closely tied to the market, currency, economic, political, regulatory, geopolitical, or other conditions in the countries or regions in which the fund invests and could be more volatile than the performance of more geographically-diversified funds.    Growth Company Risk: The stocks of growth companies can be more sensitive to the company's earnings and more volatile than the market in general.    Investment Selection Risk: MFS' investment analysis and its selection of investments may not produce the intended results and/or 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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>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.</tt> <tt>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-16 of the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002516Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002516Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000002516Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002516Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparison (Reflects no deduction for fees, expenses or taxes) MSCI All Country World (ex-US) Growth Index (gross div) -0.1393 -0.0184 0.0594 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.1011 -0.0131 0.0557 A Shares Returns After Taxes on Distributions -0.1596 -0.0200 0.0594 MGRTX 0.0000 R3 Shares Returns Before Taxes 139 434 1646 <tt>R3</tt> 750 -0.1080 0.0027 0.0085 -0.0037 0.0025 0.0714 0.0137 <tt>Class R3 Shares</tt> <tt>ALL R</tt> 0.0000 MGRQX 0.0000 R2 Shares Returns Before Taxes 165 511 1922 <tt>R2</tt> 881 -0.1106 0.0027 0.0085 -0.0062 0.0050 0.0687 0.0162 <tt>Class R2 Shares</tt> <tt>ALL R</tt> 0.0000 MGRRX 0.0000 R1 Shares Returns Before Taxes 215 664 2452 <tt>R1</tt> 1139 -0.1152 0.0027 0.0085 -0.0112 0.0100 0.0633 0.0212 <tt>Class R1 Shares</tt> <tt>ALL R</tt> 0.0000 MGRVX 0.0000 R4 Shares Returns Before Taxes 114 356 1363 <tt>R4</tt> 617 -0.1063 0.0027 0.0085 -0.0013 0.0000 0.0740 0.0112 <tt>Class R4 Shares</tt> <tt>ALL R</tt> 0.0000 MGRDX 0.0000 R5 Shares Returns Before Taxes 104 325 1248 <tt>R5</tt> 563 -0.1070 0.0017 0.0085 -0.0022 0.0000 0.0729 0.0102 <tt>Class R5 Shares</tt> <tt>ALL R</tt> 0.0000 MQGIX 0.0000 I Shares Returns Before Taxes 114 356 1363 <tt>I</tt> 617 -0.1062 0.0027 0.0085 -0.0012 0.0000 0.0763 0.0112 <tt>Class I Shares</tt> <tt>I</tt> 0.0000 MGRCX 0.0000 C Shares Returns Before Taxes 315 215 664 2452 <tt>C</tt> 1139 -0.1242 0.0027 0.0085 2452 -0.0112 664 1139 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0633 0.0212 <tt>Class C Shares assuming redemption at end of period</tt> <tt>C</tt> 0.0100 MGRBX 0.0000 B Shares Returns Before Taxes 615 215 964 2261 <tt>B</tt> 1339 -0.1503 0.0027 0.0085 2261 -0.0147 664 1139 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0649 0.0212 <tt>Class B Shares assuming redemption at end of period</tt> <tt>B</tt> 0.0400 MGRAX -0.1213 lowest quarterly return the highest quarterly return 0.0575 2012-06-30 A Shares Returns Before Taxes 706 2009-06-30 984 -0.1964 0.1754 0.1499 2127 <tt>A</tt> 1282 0.1590 0.2327 -0.1597 0.0027 -0.4010 0.0085 2011-09-30 0.3765 -0.0158 0.1395 The total return for the six-month period ended -0.1085 0.3603 0.0025 0.0639 0.0137 0.2572 <tt>Class A Shares</tt> 0.0625 <tt>A</tt> 0.0100 <tt>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 8% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002515Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002515Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The fund's investment objective is to seek capital appreciation.</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>The fund is designed to provide diversification within the international asset class by investing the majority of its assets in other mutual funds advised by MFS (Massachusetts Financial Services Company, the fund's Investment adviser), referred to as underlying funds. The underlying funds are selected based on underlying fund classifications, historical risk, performance, and other factors. MFS seeks to diversify the fund's investments in terms of market capitalization (by including large, mid, and/or small cap underlying funds), by style (by including both growth and value underlying funds), and by geographic region (by including developed and emerging market underlying funds). However, MFS may invest a relatively large percentage of the underlying funds' assets in a single country, a small number of countries, or a particular geographic region. As of September 28, 2012, the fund's target allocation among underlying funds was:    MFS Emerging Markets Equity Fund       10% MFS International Growth Fund          25% MFS International New Discovery Fund   10% MFS International Value Fund           25% MFS Research International Fund        30%</tt> Summary of Key Information 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. Example 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. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.08 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. 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. Performance Information 50000 <tt>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.</tt> 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. <tt>The total return for the six-month period ended June 30, 2012 was 5.68%.  During the period(s) shown in the bar chart, the highest quarterly return was 23.90% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (19.72)% (for the calendar quarter ended September 30, 2008).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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.    The principal risks of investing in the fund are:    Investment Selection and Allocation Risk:  MFS' investment analysis, its selection of investments, and its assessment of the risk/return potential of asset classes and underlying funds may not produce the intended results and/or 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.    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 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.    Geographic Concentration Risk:  The fund's performance could be closely tied to the market, currency, economic, political, regulatory, geopolitical, or other conditions in the countries or regions in which the fund invests and could be more volatile than the performance of more geographically-diversified funds.    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.    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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>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.</tt> <tt>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 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.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002515Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002515Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000002515Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002515Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparison (Reflects no deduction for fees, expenses or taxes) MSCI All Country World (ex-US) Index (gross div) -0.1333 -0.0248 0.0598 2004-09-30 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.0934 -0.0235 0.0470 2004-09-30 A Shares Returns After Taxes on Distributions -0.1472 -0.0329 0.0486 2004-09-30 MDIHX 0.0000 R3 Shares Returns Before Taxes 134 425 -0.0003 1621 <tt>R3</tt> 737 -0.0943 0.0013 0.0000 2013-09-30 -0.0148 0.0025 0.0132 0.0135 <tt>Class R3 Shares </tt> 0.0649 2004-09-30 0.0097 <tt>ALL R</tt> 0.0000 MDIKX 0.0000 R2 Shares Returns Before Taxes 160 502 -0.0003 1898 <tt>R2</tt> 868 -0.0970 0.0013 0.0000 2013-09-30 -0.0172 0.0050 0.0157 0.0160 <tt>Class R2 Shares</tt> 0.0622 2004-09-30 0.0097 <tt>ALL R</tt> 0.0000 MDIOX 0.0000 R1 Shares Returns Before Taxes 210 655 -0.0003 2429 <tt>R1</tt> 1126 -0.1010 0.0013 0.0000 2013-09-30 -0.0221 0.0100 0.0207 0.0210 <tt>Class R1 Shares</tt> 0.0571 2004-09-30 0.0097 <tt>ALL R</tt> 0.0000 MDIJX 0.0000 I Shares Returns Before Taxes 109 347 -0.0003 1338 <tt>I</tt> 603 -0.0917 0.0013 0.0000 2013-09-30 -0.0118 0.0000 0.0107 0.0110 <tt>Class I Shares</tt> 0.0685 2004-09-30 0.0097 <tt>I</tt> 0.0000 MDIGX 0.0000 C Shares Returns Before Taxes 310 210 655 -0.0003 2429 <tt>C</tt> 1126 -0.1097 0.0013 0.0000 2013-09-30 2429 -0.0218 655 1126 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0207 0.0210 <tt>Class C Shares assuming redemption at end of period</tt> 0.0578 2004-09-30 0.0097 <tt>C</tt> 0.0100 MDIFX 0.0000 B Shares Returns Before Taxes 610 210 955 -0.0003 2237 <tt>B</tt> 1326 -0.1371 0.0013 0.0000 2013-09-30 2237 -0.0252 655 1126 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0207 0.0210 <tt>Class B Shares assuming redemption at end of period</tt> 0.0579 2004-09-30 0.0097 <tt>B</tt> 0.0400 MDINX 0.0000 529C Shares Returns Before Taxes 315 215 672 -0.0008 2521 <tt>529C</tt> 1165 -0.1110 0.0023 0.0000 2014-09-30 2521 -0.0230 672 1165 <tt>Class 529C Shares Assuming no redemption at end of period</tt> 0.0100 0.0212 0.0220 <tt>Class 529C Shares Assuming redemption at end of period</tt> 0.0561 2004-09-30 0.0097 <tt>529C</tt> 0.0100 MDIMX 0.0000 529B Shares Returns Before Taxes 615 215 972 -0.0008 2331 <tt>529B</tt> 1365 -0.1371 0.0023 0.0000 2014-09-30 2331 -0.0266 672 1165 <tt>Class 529B Shares assuming no redemption at end of period</tt> 0.0100 0.0212 0.0220 <tt>Class 529B Shares assuming redemption at end of period</tt> 0.0560 2004-09-30 0.0097 <tt>529B</tt> 0.0400 MDIEX 0.0575 529A Shares Returns Before Taxes 706 992 -0.0008 2197 <tt>529A</tt> 1307 -0.1471 0.0023 0.0000 2014-09-30 -0.0279 0.0025 0.0137 0.0145 <tt>Class 529A Shares</tt> 0.0545 2004-09-30 0.0097 <tt>529A</tt> 0.0000 MDITX 0.0000 R4 Shares Returns Before Taxes 109 347 -0.0003 1338 <tt>R4</tt> 603 -0.0913 0.0013 0.0000 2013-09-30 -0.0124 0.0000 0.0107 0.0110 <tt>Class R4 Shares</tt> 0.0678 2004-09-30 0.0097 <tt>ALL R</tt> 0.0000 MDIDX the lowest quarterly return the highest quarterly return 0.0575 2012-06-30 A Shares Returns Before Taxes 702 2009-06-30 975 -0.1972 -0.0003 0.1320 2103 <tt>A</tt> 1269 0.1277 0.2390 -0.1461 0.0013 -0.4025 0.0000 2013-09-30 2008-09-30 0.3421 -0.0265 0.1665 The total return for the six-month period ended -0.0940 0.0025 0.0132 0.0135 0.2711 <tt>Class A Shares</tt> 0.0565 2004-09-30 0.0568 0.0097 <tt>A</tt> 0.0100 <tt>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 7% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002514Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002514Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The investment objective of the fund is to seek a high level of total return consistent with a greater than moderate level of risk relative to the other MFS Asset Allocation Funds.  (The MFS Asset Allocation Funds currently include the MFS Conservative Allocation Fund, MFS Moderate Allocation Fund, MFS Growth Allocation Fund, and MFS Aggressive Growth Allocation Fund.)</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>The fund is designed to provide diversification among different asset classes by investing its assets in other mutual funds advised by MFS (Massachusetts Financial Services Company, the fund's investment adviser), referred to as underlying funds. The underlying funds are selected following a two stage asset allocation process. The first stage is a strategic asset allocation to determine the percentage of the fund's assets to be invested in the general asset classes of Bond Funds, International Stock Funds, and U.S. Stock Funds, as well as an allocation to underlying funds that have less traditional investment strategies that MFS believes provide diversification benefits when added to a portfolio consisting of stock and bond funds (referred to as Specialty Funds). The second stage involves the actual selection of underlying funds to represent the asset classes based on underlying fund classifications, historical risk, performance, and other factors. Within the stock fund allocations, MFS seeks to diversify globally (by including domestic and international underlying funds), in terms of market capitalization (by including large, mid, and small capitalization underlying funds), and by style (by including both growth and value underlying funds). Within the bond fund allocation, MFS includes underlying funds with varying degrees of interest rate and credit exposure. As of September 28, 2012, the fund's target allocation among asset classes and the underlying funds was: Bond Funds:                            20% MFS Emerging Markets Debt Fund          3% MFS Global Bond Fund                    4% MFS High Income Fund                    5% MFS Inflation-Adjusted Bond Fund        5% MFS Research Bond Fund                  3% Specialty Funds:                        8% MFS Absolute Return Fund                1% MFS Commodity Strategy Fund             4% MFS Global Real Estate Fund             3% International Stock Funds:             20% MFS Emerging Markets Equity Fund        1% MFS International Growth Fund           5% MFS International New Discovery Fund    2% MFS International Value Fund            5% MFS Research International Fund         7% U.S. Stock Funds:                      52% MFS Growth Fund                        11% MFS Mid Cap Growth Fund                 9% MFS Mid Cap Value Fund                  9% MFS New Discovery Fund                  2% MFS New Discovery Value Fund            2% MFS Research Fund                       8% MFS Value Fund                         11%</tt> Summary of Key Information 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. Example 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. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.07 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. 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. Performance Information 50000 <tt>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.</tt> 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. <tt>The total return for the six-month period ended June 30, 2012 was 6.92%. During the period(s) shown in the bar chart, the highest quarterly return was 17.14% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (20.20)% (for the calendar quarter ended December 31, 2008).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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. The principal risks of investing in the fund are: Investment Selection and Allocation Risk:  MFS' investment analysis, its selection of investments, and its assessment of the risk/return potential of asset classes and underlying funds may not produce the intended results and/or 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. 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 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. 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. Prepayment/Extension Risk:  Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument's holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. Inflation-Adjusted Debt Instruments Risk:  Interest payments on inflation-adjusted debt instruments can be unpredictable and vary based on the level of inflation. If inflation is negative, principal and income can both decline. Municipal Risk:  The price of a municipal instrument can be volatile and significantly affected by adverse tax or court rulings, legislative or political changes, changes in specific or general market and economic conditions, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in these industries can significantly affect the fund and the overall municipal market. Commodity Risk:  The value of commodities may be more volatile than the value of equity securities or debt instruments and their value may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity. The price of a commodity may be affected by demand/supply imbalances in the market for the commodity. Real Estate-Related Investment Risk:  The risks of investing in real estate-related securities include certain risks associated with the direct ownership of real estate and the real estate industry in general. These include risks related to general, regional and local economic conditions; fluctuations in interest rates; property tax rates, zoning laws, environmental regulations and other governmental action; cash flow dependency; increased operating expenses; lack of availability of mortgage funds; losses due to natural disasters; overbuilding; losses due to casualty or condemnation; changes in property values and rental rates; and other factors.  The securities of smaller real estate-related issuers can be more volatile and less liquid than securities of larger issuers and their issuers can have more limited financial resources. 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. 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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>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.</tt> <tt>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 11 of the fund's prospectus and "Waivers of Sales Charges" on page I-20 of the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002514Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002514Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000002514Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002514Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparisons (Reflects no deduction for fees, expenses or taxes) MFS Growth Allocation Fund Blended Index -0.0024 0.0058 0.0533 2002-06-28 Index Comparisons (Reflects no deduction for fees, expenses or taxes) Standard & Poor's 500 Stock Index 0.0211 -0.0025 0.0459 2002-06-28 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.0496 -0.0005 0.0433 2002-06-28 A Shares Returns After Taxes on Distributions -0.0846 -0.0049 0.0461 2002-06-28 MAGEX 0.0000 R3 Shares Returns Before Taxes 119 372 0.0000 1420 <tt>R3</tt> 644 -0.0233 0.0011 0.0000 0.0151 0.0025 0.0117 0.0117 <tt>Class R3 Shares</tt> 0.0591 2002-06-28 0.0081 <tt>ALL R</tt> 0.0000 MGALX 0.0000 R2 Shares Returns Before Taxes 145 449 0.0000 1702 <tt>R2</tt> 776 -0.0258 0.0011 0.0000 0.0125 0.0050 0.0142 0.0142 <tt>Class R2 Shares</tt> 0.0561 2002-06-28 0.0081 <tt>ALL R</tt> 0.0000 MAGMX 0.0000 R1 Shares Returns Before Taxes 195 603 0.0000 2243 <tt>R1</tt> 1037 -0.0300 0.0011 0.0000 0.0077 0.0100 0.0192 0.0192 <tt>Class R1 Shares</tt> 0.0513 2002-06-28 0.0081 <tt>ALL R</tt> 0.0000 MGWIX 0.0000 I Shares Returns Before Taxes 94 293 0.0000 1131 <tt>I</tt> 509 -0.0201 0.0011 0.0000 0.0180 0.0000 0.0092 0.0092 <tt>Class I Shares</tt> 0.0628 2002-06-28 0.0081 <tt>I</tt> 0.0000 MCGWX 0.0000 C Shares Returns Before Taxes 295 195 603 0.0000 2243 <tt>C</tt> 1037 -0.0406 0.0011 0.0000 2243 0.0078 603 1037 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0192 0.0192 <tt>Class C Shares assuming redemption at end of period</tt> 0.0522 2002-06-28 0.0081 <tt>C</tt> 0.0100 MBGWX 0.0000 B Shares Returns Before Taxes 595 195 903 0.0000 2048 <tt>B</tt> 1237 -0.0690 0.0011 0.0000 2048 0.0044 603 1037 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0192 0.0192 <tt>Class B Shares assuming redemption at end of period</tt> 0.0534 2002-06-28 0.0081 <tt>B</tt> 0.0400 ECGWX 0.0000 529C Shares Returns Before Taxes 300 200 629 -0.0005 2344 <tt>529C</tt> 1083 -0.0410 0.0021 0.0000 2013-09-30 2344 0.0065 629 1083 <tt>Class 529C Shares assuming no redemption at end of period</tt> 0.0100 0.0197 0.0202 <tt>Class 529C Shares assuming redemption at end of period</tt> 0.0502 2002-06-28 0.0081 <tt>529C</tt> 0.0100 EBGWX 0.0000 529B Shares Returns Before Taxes 600 200 929 -0.0005 2151 <tt>529B</tt> 1283 -0.0688 0.0021 0.0000 2013-09-30 2151 0.0031 629 1083 <tt>Class 529B Shares assuming no redemption at end period</tt> 0.0100 0.0197 0.0202 <tt>Class 529B Shares assuming redemption at end of period</tt> 0.0513 2002-06-28 0.0081 <tt>529B</tt> 0.0400 EAGWX 0.0575 529A Shares Returns Before Taxes 692 950 -0.0005 2017 <tt>529A</tt> 1227 -0.0796 0.0021 0.0000 2013-09-30 0.0018 0.0025 0.0122 0.0127 <tt>Class 529A Shares</tt> 0.0508 2002-06-28 0.0081 <tt>529A</tt> 0.0000 MAGJX 0.0000 R4 Shares Returns Before Taxes 94 293 0.0000 1131 <tt>R4</tt> 509 -0.0209 0.0011 0.0000 0.0179 0.0000 0.0092 0.0092 <tt>Class R4 Shares</tt> 0.0622 2002-06-28 0.0081 <tt>ALL R</tt> 0.0000 MAGWX lowest quarterly return highest quarterly return 0.0575 2012-06-30 A Shares Returns Before Taxes 687 2009-06-30 925 -0.2020 0.1375 0.0000 0.1671 1914 <tt>A</tt> 1182 0.0885 0.1714 -0.0794 0.0011 -0.3442 0.0000 2008-12-31 0.3233 0.0030 0.0666 The total return for the six-month period ended -0.0233 0.2616 0.0025 0.0117 0.0117 0.1261 <tt>Class A Shares</tt> 0.0528 2002-06-28 0.0692 0.0081 <tt>A</tt> 0.0100 <tt>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 28% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002512Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002512Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The fund's investment objective is to seek capital appreciation.</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests at least 80% of the fund's net assets in equity securities of issuers that are tied economically to emerging market countries. Emerging market countries include countries located in Latin America, Asia, Africa, the Middle East, and developing countries of Europe, primarily Eastern Europe. MFS may also invest in equity securities of issuers that are not tied economically to emerging market countries. Equity securities include common stocks, preferred stocks, securities convertible into stocks, and depositary receipts for those securities. MFS may invest the fund's assets in companies of any size. MFS may invest a large percentage of the fund's assets in issuers in a single country, a small number of countries, or a particular geographic region. MFS may invest a relatively large percentage of the fund's assets in a single issuer or a small number of issuers. 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.</tt> Summary of Key Information 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. Example 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. The annual fund operating expenses for Class R5 shares are based on estimated "Other Expenses" for the current fiscal year expressed as a percentage of the fund's estimated average net assets during the period. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.28 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. 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. Performance Information 50000 <tt>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.</tt> 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. <tt>The total return for the six-month period ended June 30, 2012 was 5.55%. During the period(s) shown in the bar chart, the highest quarterly return was 30.53% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (30.59)% (for the calendar quarter ended September 30, 2008).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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. The principal risks of investing in the fund are: 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 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. Geographic Concentration Risk:  The fund's performance could be closely tied to the market, currency, economic, political, regulatory, geopolitical, or other conditions in the countries or regions in which the fund invests and could be more volatile than the performance of more geographically-diversified funds. Issuer Focus Risk:  The fund's performance could be more volatile than the performance of more diversified funds. Investment Selection Risk:  MFS' investment analysis and its selection of investments may not produce the intended results and/or 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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>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.</tt> <tt>This table describes the fees and expenses that you may pay when you buy and hold shares of the fund. Expenses for Class A, Class B, Class C, Class I, Class R1, Class R2, Class R3, and Class R4 shares have been adjusted to reflect current fee arrangements. The annual fund operating expenses for Class R5 shares are based on estimated "Other Expenses" for the current fiscal year expressed as a percentage of the fund's estimated average net assets during the period. 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.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002512Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002512Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000002512Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002512Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparison (Reflects no deduction for fees, expenses or taxes) MSCI Emerging Markets Index (gross div) -0.1817 0.0270 0.1420 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.1501 -0.0076 0.1083 A Shares Returns After Taxes on Distributions -0.2337 -0.0170 0.1136 MEMJX 0.0000 R5 Shares Returns Before Taxes 138 433 -0.0001 1645 <tt>R5</tt> 749 -0.1861 0.0033 0.0104 2013-09-30 0.0051 0.0000 0.1317 0.0136 0.0137 <tt>Class R5 Shares</tt> <tt>ALL R </tt> 0.0000 MEMHX 0.0000 R4 Shares Returns Before Taxes 149 464 -0.0001 1757 <tt> R4</tt> 802 -0.1861 0.0043 0.0104 2013-09-30 0.0052 0.0000 0.1318 0.0146 0.0147 <tt>Class R4 Shares</tt> <tt>ALL R</tt> 0.0000 MEMGX 0.0000 R3 Shares Returns Before Taxes 174 541 -0.0001 2029 <tt>R3</tt> 932 -0.1882 0.0043 0.0104 2013-09-30 0.0026 0.0025 0.1289 0.0171 0.0172 <tt>Class R3 Shares</tt> <tt>ALL R</tt> 0.0000 MEMFX 0.0000 R2 Shares Returns Before Taxes 199 617 -0.0001 2295 <tt>R2 </tt> 1061 -0.1902 0.0043 0.0104 2013-09-30 0.0002 0.0050 0.1261 0.0196 0.0197 <tt>Class R2 Shares</tt> <tt>ALL R</tt> 0.0000 MEMRX 0.0000 R1 Shares Returns Before Taxes 249 769 -0.0001 2805 <tt>R1</tt> 1315 -0.1940 0.0043 0.0104 2013-09-30 -0.0048 0.0100 0.1205 0.0246 0.0247 <tt>Class R1 Shares</tt> <tt>ALL R</tt> 0.0000 MEMIX 0.0000 I Shares Returns Before Taxes 149 464 -0.0001 1757 <tt>I</tt> 802 -0.1861 0.0043 0.0104 2013-09-30 0.0051 0.0000 0.1317 0.0146 0.0147 <tt>Class I Shares</tt> <tt>I</tt> 0.0000 MEMCX 0.0000 C Shares Returns Before Taxes 349 249 769 -0.0001 2805 <tt>C</tt> 1315 -0.2020 0.0043 0.0104 2013-09-30 2805 -0.0048 769 1315 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.1205 0.0246 0.0247 <tt>Class C Shares assuming redemption at end of period</tt> <tt>C</tt> 0.0100 MEMBX 0.0000 B Shares Returns Before Taxes 649 249 1069 -0.0001 2621 <tt>B</tt> 1515 -0.2265 0.0043 0.0104 2013-09-30 2621 -0.0078 769 1315 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.1222 0.0246 0.0247 <tt>Class B Shares assuming redemption at end of period</tt> <tt>B</tt> 0.0400 MEMAX -0.0284 lowest quarterly return highest quarterly return 0.0575 2012-06-30 A Shares Returns Before Taxes 739 2009-06-30 1085 -0.3059 0.2671 -0.0001 0.2307 2488 <tt>A</tt> 1454 0.3546 0.3053 -0.2348 0.0043 -0.5555 0.0104 2013-09-30 2008-09-30 0.6810 -0.0095 0.3548 The total return for the six-month period ended -0.1881 0.5202 0.0025 0.1211 0.0171 0.0172 0.2975 <tt>Class A Shares</tt> 0.0555 <tt>A</tt> 0.0100 <tt>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 4% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002510Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002510Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The investment objective of the fund is to seek a high level of total return consistent with a conservative level of risk relative to the other MFS Asset Allocation Funds.  (The MFS Asset Allocation Funds currently include the MFS Conservative Allocation Fund, MFS Moderate Allocation Fund, MFS Growth Allocation Fund, and MFS Aggressive Growth Allocation Fund.)</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>The fund is designed to provide diversification among different asset classes by investing its assets in other mutual funds advised by MFS (Massachusetts Financial Services Company, the fund's investment adviser), referred to as underlying funds. The underlying funds are selected following a two stage asset allocation process. The first stage is a strategic asset allocation to determine the percentage of the fund's assets to be invested in the general asset classes of Bond Funds, International Stock Funds, and U.S. Stock Funds, as well as an allocation to underlying funds that have less traditional investment strategies that MFS believes provide diversification benefits when added to a portfolio consisting of stock and bond funds (referred to as Specialty Funds). The second stage involves the actual selection of underlying funds to represent the asset classes based on underlying fund classifications, historical risk, performance, and other factors. Within the stock fund allocations, MFS seeks to diversify globally (by including domestic and international underlying funds), in terms of market capitalization (by including large, mid, and small capitalization underlying funds), and by style (by including both growth and value underlying funds). Within the bond fund allocation, MFS includes underlying funds with varying degrees of interest rate and credit exposure. As of September 28, 2012, the fund's target allocation among asset classes and the underlying funds was: Bond Funds:                        60% MFS Emerging Markets Debt Fund      3% MFS Global Bond Fund                5% MFS Government Securities Fund     10% MFS High Income Fund                5% MFS Inflation-Adjusted Bond Fund   10% MFS Limited Maturity Fund          10% MFS Research Bond Fund             17% Specialty Funds:                    4% MFS Absolute Return Fund            2% MFS Commodity Strategy Fund         1% MFS Global Real Estate Fund         1% International Stock Funds:          8% MFS International Growth Fund       2% MFS International Value Fund        2% MFS Research International Fund     4% U.S. Stock Funds:                  28% MFS Growth Fund                     6% MFS Mid Cap Growth Fund             4% MFS Mid Cap Value Fund              4% MFS New Discovery Fund              1% MFS New Discovery Value Fund        1% MFS Research Fund                   6% MFS Value Fund                      6%</tt> Summary of Key Information 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. Example 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. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.04 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. 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. Performance Information 50000 <tt>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.</tt> 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. <tt>The total return for the six-month period ended June 30, 2012 was 4.93%. During the period(s) shown in the bar chart, the highest quarterly return was 10.76% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (9.28)% (for the calendar quarter ended December 31, 2008).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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. The principal risks of investing in the fund are: Investment Selection and Allocation Risk:  MFS' investment analysis, its selection of investments, and its assessment of the risk/return potential of asset classes and underlying funds may not produce the intended results and/or 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. 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. Prepayment/Extension Risk:  Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument's holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. Inflation-Adjusted Debt Instruments Risk:  Interest payments on inflation-adjusted debt instruments can be unpredictable and vary based on the level of inflation. If inflation is negative, principal and income can both decline. Municipal Risk:  The price of a municipal instrument can be volatile and significantly affected by adverse tax or court rulings, legislative or political changes, changes in specific or general market and economic conditions, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in these industries can significantly affect the fund and the overall municipal market. Commodity Risk:  The value of commodities may be more volatile than the value of equity securities or debt instruments and their value may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity. The price of a commodity may be affected by demand/supply imbalances in the market for the commodity. Real Estate-Related Investment Risk: The risks of investing in real estate-related securities include certain risks associated with the direct ownership of real estate and the real estate industry in general. These include risks related to general, regional and local economic conditions; fluctuations in interest rates; property tax rates, zoning laws, environmental regulations and other governmental action; cash flow dependency; increased operating expenses; lack of availability of mortgage funds; losses due to natural disasters; overbuilding; losses due to casualty or condemnation; changes in property values and rental rates; and other factors.  The securities of smaller real estate-related issuers can be more volatile and less liquid than securities of larger issuers and their issuers can have more limited financial resources. 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. Leveraging Risk:  Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. 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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>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.</tt> <tt>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 11 of the fund's prospectus and "Waivers of Sales Charges" on page I-20 of the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002510Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002510Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000002510Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002510Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparisons (Reflects no deduction for fees, expenses or taxes) MFS Conservative Allocation Fund Blended Index 0.0458 0.0381 0.0543 2002-06-28 Index Comparisons (Reflects no deduction for fees, expenses or taxes) Barclays U.S. Aggregate Bond Index 0.0784 0.0650 0.0564 2002-06-28 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.0216 0.0225 0.0370 2002-06-28 A Shares Returns After Taxes on Distributions -0.0433 0.0223 0.0393 2002-06-28 MACNX 0.0000 R3 Shares Returns Before Taxes 105 328 0.0000 1259 <tt>R3</tt> 569 0.0236 0.0009 0.0000 0.0451 0.0025 0.0103 0.0103 <tt>Class R3 Shares</tt> 0.0547 2002-06-28 0.0069 <tt>ALL R</tt> 0.0000 MCARX 0.0000 R2 Shares Returns Before Taxes 130 406 0.0000 1545 <tt>R2</tt> 702 0.0222 0.0009 0.0000 0.0427 0.0050 0.0128 0.0128 <tt>Class R2 Shares</tt> 0.0516 2002-06-28 0.0069 <tt>ALL R</tt> 0.0000 MACKX 0.0000 R1 Shares Returns Before Taxes 181 560 0.0000 2095 <tt>R1</tt> 964 0.0166 0.0009 0.0000 0.0374 0.0100 0.0178 0.0178 <tt>Class R1 Shares</tt> 0.0468 2002-06-28 0.0069 <tt>ALL R</tt> 0.0000 MACIX 0.0000 I Shares Returns Before Taxes 80 249 0.0000 966 <tt>I</tt> 433 0.0265 0.0009 0.0000 0.0481 0.0000 0.0078 0.0078 <tt>Class I Shares</tt> 0.0582 2002-06-28 0.0069 <tt>I</tt> 0.0000 MACVX 0.0000 C Shares Returns Before Taxes 281 181 560 0.0000 2095 <tt>C</tt> 964 0.0064 0.0009 0.0000 2095 0.0378 560 964 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0178 0.0178 <tt>Class C Shares assuming redemption at end of period</tt> 0.0477 2002-06-28 0.0069 <tt>C</tt> 0.0100 MACBX 0.0000 B Shares Returns Before Taxes 581 181 860 0.0000 1897 <tt>B</tt> 1164 -0.0233 0.0009 0.0000 1897 0.0343 560 964 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0178 0.0178 <tt>Class B Shares assuming redemption at end of period</tt> 0.0489 2002-06-28 0.0069 <tt>B</tt> 0.0400 ECACX 0.0000 529C Shares Returns Before Taxes 286 186 586 -0.0005 2197 <tt>529C</tt> 1011 0.0064 0.0019 0.0000 2013-09-30 2197 0.0364 586 1011 <tt>Class 529C Shares assuming no redemption at end of period</tt> 0.0100 0.0183 0.0188 <tt>Class 529C Shares assuming redemption at end of period</tt> 0.0458 2002-06-28 0.0069 <tt>529C</tt> 0.0100 EBCAX 0.0000 529B Shares Returns Before Taxes 586 186 886 -0.0005 2001 <tt>529B</tt> 1211 -0.0234 0.0019 0.0000 2013-09-30 2001 0.0330 586 1011 <tt>Class 529B Shares assuming no redemption at end of period</tt> 0.0100 0.0183 0.0188 <tt>Class 529B Shares assuming redemption at end of period</tt> 0.0469 2002-06-28 0.0069 <tt>529B</tt> 0.0400 ECLAX 0.0575 529A Shares Returns Before Taxes 679 909 -0.0005 1866 <tt>529A</tt> 1157 -0.0353 0.0019 0.0000 2013-09-30 0.0314 0.0025 0.0108 0.0113 <tt>Class 529A Shares</tt> 0.0463 2002-06-28 0.0069 <tt>529A</tt> 0.0000 MACJX 0.0000 R4 Shares Returns Before Taxes 80 249 0.0000 966 <tt>R4</tt> 433 0.0275 0.0009 0.0000 0.0480 0.0000 0.0078 0.0078 <tt>Class R4 Shares</tt> 0.0577 2002-06-28 0.0069 <tt>ALL R </tt> 0.0000 MACFX the lowest quarterly return the highest quarterly return 0.0575 2012-06-30 A Shares Returns Before Taxes 674 2009-06-30 884 -0.0928 0.0723 0.0000 0.1129 1762 <tt>A</tt> 1111 0.0733 0.1076 -0.0346 0.0009 -0.1660 0.0000 2008-12-31 0.2215 0.0327 0.0394 The total return for the six-month period ended 0.0243 0.1165 0.0025 0.0103 0.0103 0.0865 <tt>Class A Shares</tt> 0.0482 2002-06-28 0.0493 0.0069 <tt>A</tt> 0.0100 <tt>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 6% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002507Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002507Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The investment objective of the fund is to seek a high level of total return consistent with a moderate level of risk relative to the other MFS Asset Allocation Funds.  (The MFS Asset Allocation Funds currently include the MFS Conservative Allocation Fund, MFS Moderate Allocation Fund, MFS Growth Allocation Fund, and MFS Aggressive Growth Allocation Fund.)</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>The fund is designed to provide diversification among different asset classes by investing its assets in other mutual funds advised by MFS (Massachusetts Financial Services Company, the fund's investment adviser), referred to as underlying funds. The underlying funds are selected following a two stage asset allocation process. The first stage is a strategic asset allocation to determine the percentage of the fund's assets to be invested in the general asset classes of Bond Funds, International Stock Funds, and U.S. Stock Funds, as well as an allocation to underlying funds that have less traditional investment strategies that MFS believes provide diversification benefits when added to a portfolio consisting of stock and bond funds (referred to as Specialty Funds). The second stage involves the actual selection of underlying funds to represent the asset classes based on underlying fund classifications, historical risk, performance, and other factors. Within the stock fund allocations, MFS seeks to diversify globally (by including domestic and international underlying funds), in terms of market capitalization (by including large, mid, and small capitalization underlying funds), and by style (by including both growth and value underlying funds). Within the bond fund allocation, MFS includes underlying funds with varying degrees of interest rate and credit exposure. As of September 28, 2012, the fund's target allocation among asset classes and the underlying funds was: Bond Funds:                             40% MFS Emerging Markets Debt Fund           3% MFS Global Bond Fund                     5% MFS Government Securities Fund          10% MFS High Income Fund                     5% MFS Inflation-Adjusted Bond Fund         5% MFS Research Bond Fund                  12% Specialty Funds:                         6% MFS Absolute Return Fund                 1% MFS Commodity Strategy Fund              3% MFS Global Real Estate Fund              2% International Stock Funds:              13% MFS International Growth Fund            3% MFS International New Discovery Fund     1% MFS International Value Fund             3% MFS Research International Fund          6% U.S. Stock Funds:                       41% MFS Growth Fund                          8% MFS Mid Cap Growth Fund                  7% MFS Mid Cap Value Fund                   7% MFS New Discovery Fund                 1.5% MFS New Discovery Value Fund           1.5% MFS Research Fund                        8% MFS Value Fund                           8%</tt> Summary of Key Information 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. Example 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. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.06 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. 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. Performance Information 50000 <tt>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.</tt> 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. <tt>The total return for the six-month period ended June 30, 2012 was 5.90%. During the period(s) shown in the bar chart, the highest quarterly return was 13.80% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (15.13)% (for the calendar quarter ended December 31, 2008).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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. The principal risks of investing in the fund are: Investment Selection and Allocation Risk:  MFS' investment analysis, its selection of investments, and its assessment of the risk/return potential of asset classes and underlying funds may not produce the intended results and/or 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. 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 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. 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. Prepayment/Extension Risk:  Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument's holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. Inflation-Adjusted Debt Instruments Risk:  Interest payments on inflation-adjusted debt instruments can be unpredictable and vary based on the level of inflation. If inflation is negative, principal and income can both decline. Municipal Risk:  The price of a municipal instrument can be volatile and significantly affected by adverse tax or court rulings, legislative or political changes, changes in specific or general market and economic conditions, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in these industries can significantly affect the fund and the overall municipal market. Commodity Risk:  The value of commodities may be more volatile than the value of equity securities or debt instruments and their value may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity. The price of a commodity may be affected by demand/supply imbalances in the market for the commodity. Real Estate-Related Investment Risk:  The risks of investing in real estate-related securities include certain risks associated with the direct ownership of real estate and the real estate industry in general. These include risks related to general, regional and local economic conditions; fluctuations in interest rates; property tax rates, zoning laws, environmental regulations and other governmental action; cash flow dependency; increased operating expenses; lack of availability of mortgage funds; losses due to natural disasters; overbuilding; losses due to casualty or condemnation; changes in property values and rental rates; and other factors.  The securities of smaller real estate-related issuers can be more volatile and less liquid than securities of larger issuers and their issuers can have more limited financial resources. 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. 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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>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.</tt> <tt>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 11 of the fund's prospectus and "Waivers of Sales Charges" on page I-20 of the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002507Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002507Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000002507Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002507Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparisons (Reflects no deduction for fees, expenses or taxes) MFS Moderate Allocation Fund Blended Index 0.0222 0.0230 0.0537 2002-06-28 Index Comparisons (Reflects no deduction for fees, expenses or taxes) Standard & Poor's 500 Stock Index 0.0211 -0.0025 0.0459 2002-06-28 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.0344 0.0122 0.0411 2002-06-28 A Shares Returns After Taxes on Distributions -0.0622 0.0103 0.0438 2002-06-28 MAMHX 0.0000 R3 Shares Returns Before Taxes 111 347 0.0000 1329 <tt>R3</tt> 601 0.0030 0.0009 0.0000 0.0319 0.0025 0.0109 0.0109 <tt>Class R3 Shares</tt> 0.0585 2002-06-28 0.0075 <tt>ALL R </tt> 0.0000 MARRX 0.0000 R2 Shares Returns Before Taxes 136 425 0.0000 1613 <tt>R2</tt> 734 -0.0004 0.0009 0.0000 0.0292 0.0050 0.0134 0.0134 <tt>Class R2 Shares </tt> 0.0554 2002-06-28 0.0075 <tt>ALL R</tt> 0.0000 MAMFX 0.0000 R1 Shares Returns Before Taxes 187 579 0.0000 2159 <tt>R1</tt> 996 -0.0053 0.0009 0.0000 0.0242 0.0100 0.0184 0.0184 <tt>Class R1 Shares </tt> 0.0504 2002-06-28 0.0075 <tt>ALL R</tt> 0.0000 MMAIX 0.0000 I Shares Returns Before Taxes 86 268 0.0000 1037 <tt>I</tt> 466 0.0053 0.0009 0.0000 0.0348 0.0000 0.0084 0.0084 <tt>Class I Shares</tt> 0.0621 2002-06-28 0.0075 <tt>I</tt> 0.0000 MMACX 0.0000 C Shares Returns Before Taxes 287 187 579 0.0000 2159 <tt>C</tt> 996 -0.0142 0.0009 0.0000 2159 0.0245 579 996 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0184 0.0184 <tt>Class C Shares assuming redemption at end of period</tt> 0.0514 2002-06-28 0.0075 <tt>C</tt> 0.0100 MMABX 0.0000 B Shares Returns Before Taxes 587 187 879 0.0000 1962 <tt>B</tt> 1196 -0.0433 0.0009 0.0000 1962 0.0209 579 996 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0184 0.0184 <tt>Class B Shares assuming redemption at end of period</tt> 0.0526 2002-06-28 0.0075 <tt>B</tt> 0.0400 ECMAX 0.0000 529C Shares Returns Before Taxes 292 192 604 -0.0005 2260 <tt>529C</tt> 1042 -0.0150 0.0019 0.0000 2013-09-30 2260 0.0230 604 1042 <tt>Class 529C Shares assuming no redemption at end of period</tt> 0.0100 0.0189 0.0194 <tt>Class 529C Shares assuming redemption at end of period</tt> 0.0495 2002-06-28 0.0075 <tt>529C</tt> 0.0100 EBMDX 0.0000 529B Shares Returns Before Taxes 592 192 904 -0.0005 2066 <tt>529B</tt> 1242 -0.0441 0.0019 0.0000 2013-09-30 2066 0.0196 604 1042 <tt>Class 529B Shares assuming no redemption at end of period</tt> 0.0100 0.0189 0.0194 <tt>Class 529B Shares assuming redemption at end of period</tt> 0.0507 2002-06-28 0.0075 <tt>529B</tt> 0.0400 EAMDX 0.0575 529A Shares Returns Before Taxes 685 926 -0.0005 1931 <tt>529A</tt> 1187 -0.0555 0.0019 0.0000 2013-09-30 0.0183 0.0025 0.0114 0.0119 <tt>Class 529A Shares </tt> 0.0500 2002-06-28 0.0075 <tt>529A</tt> 0.0000 MAMJX 0.0000 R4 Shares Returns Before Taxes 86 268 0.0000 1037 <tt>R4</tt> 466 0.0053 0.0009 0.0000 0.0345 0.0000 0.0084 0.0084 <tt>Class R4 Shares </tt> 0.0613 2002-06-28 0.0075 <tt>ALL R</tt> 0.0000 MAMAX the lowest quarterly return the highest quarterly return 0.0575 2012-06-30 A Shares Returns Before Taxes 680 2009-06-30 902 -0.1513 0.1059 0.0000 0.1453 1827 <tt>A</tt> 1141 0.0826 0.1380 -0.0548 0.0009 -0.2604 0.0000 2008-12-31 0.2714 0.0196 0.0512 The total return for the six-month period ended 0.0029 0.1895 0.0025 0.0109 0.0109 0.1026 <tt>Class A Shares</tt> 0.0518 2002-06-28 0.0590 0.0075 <tt>A</tt> 0.0100 <tt>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 11% of the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002506Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002506Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The investment objective of the fund is to seek a high level of total return consistent with an aggressive level of risk relative to the other MFS Asset Allocation Funds.  (The MFS Asset Allocation Funds currently include the MFS Conservative Allocation Fund, MFS Moderate Allocation Fund, MFS Growth Allocation Fund, and MFS Aggressive Growth Allocation Fund.)</tt> <tt>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 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.</tt> Performance Table. Reflects no deduction for fees, expenses or taxes <tt>The fund is designed to provide diversification among different asset classes by investing its assets in other mutual funds advised by MFS (Massachusetts Financial Services Company, the fund's investment adviser), referred to as underlying funds. The underlying funds are selected following a two stage asset allocation process. The first stage is a strategic asset allocation to determine the percentage of the fund's assets to be invested in the general asset classes of Bond Funds, International Stock Funds, and U.S. Stock Funds, as well as an allocation to underlying funds that have less traditional investment strategies that MFS believes provide diversification benefits when added to a portfolio consisting of stock and bond funds (referred to as Specialty Funds). The second stage involves the actual selection of underlying funds to represent the asset classes based on underlying fund classifications, historical risk, performance, and other factors. Within the stock fund allocations, MFS seeks to diversify globally (by including domestic and international underlying funds), in terms of market capitalization (by including large, mid, and small capitalization underlying funds), and by style (by including both growth and value underlying funds). As of September 28, 2012, the fund's target allocation among asset classes and the underlying funds was: Bond Funds:                              0% Specialty Funds:                        10% MFS Commodity Strategy Fund              5% MFS Global Real Estate Fund              5% International Stock Funds:              30% MFS Emerging Markets Equity Fund         2% MFS International Growth Fund            8% MFS International New Discovery Fund     4% MFS International Value Fund             8% MFS Research International Fund          8% U.S. Stock Funds:                       60% MFS Growth Fund                         13% MFS Mid Cap Growth Fund                 10% MFS Mid Cap Value Fund                  10% MFS New Discovery Fund                 2.5% MFS New Discovery Value Fund           2.5% MFS Research Fund                        9% MFS Value Fund                          13%</tt> Summary of Key Information 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. Example 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. Investment Objective The fund's past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. Principal Risks Shareholder Fees (fees paid directly from your investment): Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 0.11 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. 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. Performance Information 50000 <tt>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.</tt> 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. <tt>The total return for the six-month period ended June 30, 2012 was 7.42%. During the period(s) shown in the bar chart, the highest quarterly return was 19.81% (for the calendar quarter ended June 30, 2009) and the lowest quarterly return was (24.63)% (for the calendar quarter ended December 31, 2008).</tt> 1-800-225-2606 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): Average Annual Total Returns (for the Periods Ended December 31, 2011) <tt>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.</tt> Portfolio Turnover <tt>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. The principal risks of investing in the fund are: Investment Selection and Allocation Risk:  MFS' investment analysis, its selection of investments, and its assessment of the risk/return potential of asset classes and underlying funds may not produce the intended results and/or 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. 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 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.    Commodity Risk:  The value of commodities may be more volatile than the value of equity securities or debt instruments and their value may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity. The price of a commodity may be affected by demand/supply imbalances in the market for the commodity. Real Estate-Related Investment Risk:  The risks of investing in real estate-related securities include certain risks associated with the direct ownership of real estate and the real estate industry in general. These include risks related to general, regional and local economic conditions; fluctuations in interest rates; property tax rates, zoning laws, environmental regulations and other governmental action; cash flow dependency; increased operating expenses; lack of availability of mortgage funds; losses due to natural disasters; overbuilding; losses due to casualty or condemnation; changes in property values and rental rates; and other factors.  The securities of smaller real estate-related issuers can be more volatile and less liquid than securities of larger issuers and their issuers can have more limited financial resources. 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. 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.</tt> Fees and Expenses 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. Principal Investment Strategies mfs.com <tt>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.</tt> <tt>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 9 of the fund's prospectus and "Waivers of Sales Charges" on page I-20 of the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002506Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002506Member column dei_LegalEntityAxis compact * column rr_PerformanceMeasureAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> 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. <div style="display:none">~ http://www.mfs.com/role/ExpenseExampleNoRedemption_S000002506Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002506Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparisons (Reflects no deduction for fees, expenses or taxes) MFS Aggressive Growth Allocation Fund Blended Index -0.0332 -0.0125 0.0476 2002-06-28 Index Comparisons (Reflects no deduction for fees, expenses or taxes) Standard & Poor's 500 Stock Index 0.0211 -0.0025 0.0459 2002-06-28 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.0656 -0.0118 0.0399 2002-06-28 A Shares Returns After Taxes on Distributions -0.1068 -0.0179 0.0427 2002-06-28 MAAHX 0.0000 R3 Shares Returns Before Taxes 126 398 -0.0002 1521 <tt>R3</tt> 690 -0.0500 0.0015 0.0000 -0.0011 0.0124 0.0126 <tt>Class R3 Shares</tt> 0.0532 2002-06-28 0.0086 <tt>ALL R</tt> 0.0000 MAWAX 0.0000 R2 Shares Returns Before Taxes 152 475 -0.0002 1800 <tt>R2</tt> 822 -0.0527 0.0015 0.0000 -0.0037 0.0050 0.0149 0.0151 <tt>Class R2 Shares</tt> 0.0502 2002-06-28 0.0086 <tt>ALL R </tt> 0.0000 MAAFX 0.0000 R1 Shares Returns Before Taxes 202 629 -0.0002 2336 <tt>R1</tt> 1081 -0.0570 0.0015 0.0000 -0.0085 0.0100 0.0199 0.0201 <tt>Class R1 Shares</tt> 0.0453 2002-06-28 0.0086 <tt>ALL R </tt> 0.0000 MIAGX 0.0000 I Shares Returns Before Taxes 101 320 -0.0002 1234 <tt>I</tt> 556 -0.0482 0.0015 0.0000 0.0017 0.0000 0.0099 0.0101 <tt>Class I Shares</tt> 0.0568 2002-06-28 0.0086 <tt>I</tt> 0.0000 MCAGX 0.0000 C Shares Returns Before Taxes 302 202 629 -0.0002 2336 <tt>C</tt> 1081 -0.0661 0.0015 0.0000 2336 -0.0082 629 1081 <tt>Class C no redemption at end of period</tt> 0.0100 0.0199 0.0201 <tt>Class C Shares assuming redemption at end of period</tt> 0.0463 2002-06-28 0.0086 <tt>C</tt> 0.0100 MBAGX 0.0000 B Shares Returns Before Taxes 602 202 929 -0.0002 2143 <tt>B</tt> 1281 -0.0953 0.0015 0.0000 2143 -0.0118 629 1081 <tt>Class B Shares no redemption at end of period</tt> 0.0100 0.0199 0.0201 <tt>Class B Shares assuming redemption at end of period</tt> 0.0477 2002-06-28 0.0086 <tt>B</tt> 0.0400 ECAAX 0.0000 529C Shares Returns Before Taxes 307 207 654 -0.0007 2436 <tt>529C</tt> 1128 -0.0671 0.0025 0.0000 2013-09-30 2436 -0.0096 654 1128 <tt>Class 529C no redemption at end of period</tt> 0.0100 0.0204 0.0211 <tt>Class 529C Shares assuming redemption at end of period</tt> 0.0443 2002-06-28 0.0086 <tt>529C</tt> 0.0100 EBAAX