485BPOS 2012-08-31 0000063068 2012-12-29 MFS SERIES TRUST IV false 2012-12-27 2012-12-29 <tt>The fund pays transaction costs, such as commissions, when it buys and sells<br />securities (or "turns over" its portfolio). A higher portfolio turnover rate <br />may indicate higher transaction costs and may result in higher taxes when <br />shares are held in a taxable account. These transaction costs, which are not <br />reflected in "Annual Fund Operating Expenses" or in the "Example," affect <br />the fund's performance.&#xA0;&#xA0;For the period from the fund's commencement of <br />operations on December 16, 2011 to the fund's fiscal year end of <br />August 31, 2012, the fund's portfolio turnover rate was 40% of the <br />average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000035048Member 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<br />with the cost of investing in other mutual funds.<br />&#xA0;&#xA0;<br />The example assumes that: you invest $10,000 in the fund for the time periods<br />indicated and you redeem your shares at the end of the time periods (unless<br />otherwise indicated); your investment has a 5% return each year; and the fund's<br />operating expenses remain the same.</tt> <tt>MFS (Massachusetts Financial Services Company, the fund's investment adviser)<br />normally invests the fund's assets primarily in U.S. and foreign equity<br />securities, including emerging market equity securities. Equity securities<br />include common stocks, preferred stocks, securities convertible into stocks, <br />and depositary receipts for such securities.<br /> <br />MFS may invest a large percentage of the fund's assets in issuers in a single<br />country, a small number of countries, or a particular geographic region.<br /> <br />In selecting investments for the fund, MFS is not constrained to any particular<br />investment style. MFS may invest the fund's assets in the stocks of companies <br />it believes to have above average earnings growth potential compared to other<br />companies (growth companies), in the stocks of companies it believes are<br />undervalued compared to their perceived worth (value companies), or in a<br />combination of growth and value companies.<br />&#xA0;&#xA0;<br />While MFS may invest the fund's assets in companies of any size, MFS generally<br />focuses on companies with small to medium capitalizations.<br />&#xA0;&#xA0;<br />MFS uses a bottom-up investment approach to buying and selling investments for<br />the fund. Investments are selected primarily based on fundamental analysis of<br />individual issuers. Quantitative models that systematically evaluate issuers may<br />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 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: 0.40 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<br />lose money on your investment in the fund. An investment in the fund is not a<br />bank deposit and is not insured or guaranteed by the Federal Deposit Insurance<br />Corporation or any other governmental agency.<br />&#xA0;&#xA0;<br />The principal risks of investing in the fund are:<br />&#xA0;&#xA0;<br />Stock Market/Company Risk: Stock markets are volatile and can decline<br />significantly in response to issuer, market, economic, industry, political,<br />regulatory, geopolitical, and other conditions, as well as to investor<br />perceptions of these conditions. The price of an equity security can decrease<br />significantly in response to these conditions, and these conditions can affect <br />a single issuer or type of security, issuers within a broad market sector,<br />industry or geographic region, or the market in general.<br />&#xA0;&#xA0;<br />Small to Medium Cap Risk: The stocks of small to medium cap companies can be<br />more volatile than stocks of larger companies.<br />&#xA0;&#xA0;<br />Foreign and Emerging Markets Risk: Exposure to foreign markets, especially<br />emerging markets, through issuers or currencies can involve additional risks<br />relating to market, economic, political, regulatory, geopolitical, and other<br />conditions. These factors can make foreign investments, especially those in<br />emerging markets, more volatile and less liquid than U.S. investments. In<br />addition, foreign markets can react differently to these conditions than the<br />U.S. market. Emerging markets can have less developed markets, greater custody<br />and operational risk, less developed legal, regulatory, and accounting systems,<br />and greater political, social, and economic instability than developed markets.<br />&#xA0;&#xA0;<br />Currency Risk: The value of foreign currencies relative to the U.S. dollar<br />fluctuates in response to market, economic, political, regulatory, geopolitical,<br />and other conditions, and a decline in the value of a foreign currency versus<br />the U.S. dollar reduces the value in U.S. dollars of investments denominated in<br />that foreign currency.<br />&#xA0;&#xA0;<br />Geographic Concentration Risk: The fund's performance could be closely tied to<br />the market, currency, economic, political, regulatory, geopolitical, and other<br />conditions in the countries or regions in which the fund invests and could be<br />more volatile than the performance of more geographically-diversified funds.<br />&#xA0;&#xA0;<br />Investment Selection Risk: MFS' investment analysis and its selection of<br />investments may not produce the intended results and/or can lead to an<br />investment focus that results in the fund underperforming other funds with<br />similar investment strategies and/or underperforming the markets in which the<br />fund invests.<br />&#xA0;&#xA0;<br />Liquidity Risk: It may not be possible to sell certain investments, types of<br />investments, and/or segments of the market at any particular time or at an<br />acceptable price.</tt> Fees and Expenses Principal Investment Strategies <tt>The bar chart and performance table are not included because the fund has not<br />had a full calendar year of operations.</tt> <tt>This table describes the fees and expenses that you may pay when you buy and<br />hold shares of the fund. The annual fund operating expenses for Class R5 shares<br />are based on estimated "Other Expenses" for the current fiscal year expressed as<br />a percentage of the fund's estimated average net assets during the period.<br />&#xA0;&#xA0;<br />You may qualify for sales charge reductions if you and certain members of your<br />family invest, or agree to invest in the future, at least $50,000 in MFS Funds.<br />More information about these and other waivers and reductions is available from<br />your financial intermediary and in "Sales Charges and Waivers or Reductions" on<br />page 7 of the fund's prospectus and "Waivers of Sales Charges" on page I-12 of<br />the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000035048Member 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_S000035048Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000035048Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> GLNNX 0.0000 127 1042 -0.0313 4333 <tt>R5</tt> 1968 0.0340 0.0098 2013-12-31 0.0000 0.0125 0.0438 <tt>Class R5 Shares</tt> <tt>ALL R </tt> 0.0000 GLNMX 0.0000 127 1042 -0.0313 4333 <tt>R4</tt> 1968 0.0340 0.0098 2013-12-31 0.0000 0.0125 0.0438 <tt>Class R4 Shares</tt> <tt>ALL R </tt> 0.0000 GLNLX 0.0000 153 1115 -0.0313 4538 <tt>R3</tt> 2084 0.0340 0.0098 2013-12-31 0.0025 0.0150 0.0463 <tt>Class R3 Shares</tt> <tt>ALL R </tt> 0.0000 GLNKX 0.0000 178 1187 -0.0313 4737 <tt>R2</tt> 2198 0.0340 0.0098 2013-12-31 0.0050 0.0175 0.0488 <tt>Class R2 Shares</tt> <tt>ALL R </tt> 0.0000 GLNJX 0.0000 228 1329 -0.0313 5119 <tt>R1</tt> 2423 0.0340 0.0098 2013-12-31 0.0100 0.0225 0.0538 <tt>Class R1 Shares</tt> <tt>ALL R </tt> 0.0000 GLNIX 0.0000 127 1042 -0.0313 4333 <tt>I</tt> 1968 0.0340 0.0098 2013-12-31 0.0000 0.0125 0.0438 <tt>Class I Shares</tt> <tt>I</tt> 0.0000 GLNCX 0.0000 328 228 1329 -0.0313 5119 <tt>C</tt> 2423 0.0340 0.0098 2013-12-31 5119 1329 2423 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0225 0.0538 <tt>Class C Shares assuming redemption at end of period</tt> <tt>C</tt> 0.0100 GLNBX 0.0000 628 228 1629 -0.0313 4976 <tt>B</tt> 2623 0.0340 0.0098 2013-12-31 4976 1329 2423 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0225 0.0538 <tt>Class B Shares assuming redemption at end of period</tt> <tt>B</tt> 0.0400 GLNAX 0.0575 719 1626 -0.0313 4852 <tt>A</tt> 2539 0.0340 0.0098 2013-12-31 0.0025 0.0150 0.0463 <tt>Class A Shares</tt> <tt>A</tt> 0.0100 <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002435Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002435Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The fund's investment objective is to seek current income consistent with<br />preservation of capital and liquidity.</tt> <tt>This example is intended to help you compare the cost of investing in the fund<br />with the cost of investing in other mutual funds.<br />&#xA0;&#xA0;<br />The example assumes that: you invest $10,000 in the fund for the time periods<br />indicated and you redeem your shares at the end of the time periods; your<br />investment has a 5% return each year; and the fund's operating expenses remain<br />the same.</tt> Performance Table. <tt>MFS (Massachusetts Financial Services Company, the fund's investment adviser)<br />normally invests the fund's assets in U.S. dollar-denominated money market<br />instruments and repurchase agreements. Money market instruments include bank<br />certificates of deposit and other bank obligations of U.S. and foreign banks;<br />notes, commercial paper, and asset-backed securities of U.S. and foreign<br />issuers; U.S. and foreign government securities; and municipal instruments.<br />&#xA0;&#xA0;<br />In buying and selling investments for the fund, MFS seeks to comply with<br />Securities and Exchange Commission rules for money market funds regarding credit<br />quality, diversification, liquidity, and maturity. MFS stresses maintaining a<br />stable $1.00 share price, liquidity, and income.</tt> Summary of Key Information Example Investment Objective The fund's past performance does not necessarily indicate how the fund will perform in the future. 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: Bar Chart. Performance Information 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. <tt>The total return for the nine-month period ended September 30, 2012 was 0.00%.<br />During the period(s) shown in the bar chart, the highest quarterly return was<br />1.28% (for the calendar quarter ended September 30, 2006, and December 31, 2006)<br />and the lowest quarterly return was 0.00% (for the calendar quarter ended<br />June 30, 2009, quarter ended September 30, 2009, quarter ended December 31,<br />2009, quarter ended&#xA0;&#xA0;March 31, 2010, quarter ended June 30, 2010, quarter ended<br />September 30, 2010, quarter ended December 31, 2010, quarter ended March 31,<br />2011, quarter ended June 30, 2011, quarter ended September 30, 2011, and the<br />quarter ended December 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) Although the fund seeks to preserve the value of your investment at $1.00 per share, the fund may not achieve its objective and you could lose money on your investment in the fund. <tt>Although the fund seeks to preserve the value of your investment at $1.00 per<br />share, the fund may not achieve its objective and you could lose money on your<br />investment in the fund. An investment in the fund is not a bank deposit and is<br />not insured or guaranteed by the Federal Deposit Insurance Corporation or any<br />other governmental agency.<br />&#xA0;&#xA0;<br />The principal risks of investing in the fund are:<br />&#xA0;&#xA0;<br />Interest Rate, Credit, and Liquidity Risk:&#xA0;&#xA0;Although MFS seeks to maintain a<br />stable $1.00 share price for the fund, there is no guarantee that it will be<br />able to do so. A major increase in interest rates or a decline in the credit<br />quality of an issuer or entity providing credit support, an inactive trading<br />market for money market instruments, or adverse market, economic, political,<br />regulatory, geopolitical, and other conditions could cause the fund's share<br />price to decrease to below $1.00.<br />&#xA0;&#xA0;<br />Bank Focus Risk: Events that affect the banking or related industries may have<br />a significant adverse affect on the fund.<br />&#xA0;&#xA0;<br />Municipal Risk: The price of a municipal instrument can be volatile and<br />significantly affected by adverse tax or court rulings, legislative or political<br />changes, changes in specific or general market and economic conditions, and the<br />financial condition of municipal issuers and insurers. Because many municipal<br />instruments are issued to finance similar projects, conditions in these<br />industries can significantly affect the fund and the overall municipal market.<br />&#xA0;&#xA0;<br />Foreign Exposure Risk: Exposure to foreign markets can involve increased risks<br />due to adverse market, economic, political, regulatory, geopolitical, and other<br />conditions.<br />&#xA0;&#xA0;<br />Investment Selection Risk: MFS' investment analysis and its selection of<br />investments may not produce the intended results and/or can lead to an<br />investment focus that results in the fund underperforming other funds with<br />similar investment strategies and/or underperforming the markets in which the<br />fund invests.<br />&#xA0;&#xA0;<br />Counterparty and Third Party Risk: Transactions involving a counterparty or<br />third party other than the issuer of the instrument are subject to the credit<br />risk of the counterparty or third party, and to the counterparty's or third<br />party's ability to perform in accordance with the terms of the transaction.<br />&#xA0;&#xA0;<br />Liquidity Risk: It may not be possible to sell certain investments, types of<br />investments, and/or segments of the market at any particular time or at an<br />acceptable price.</tt> Fees and Expenses Principal Investment Strategies mfs.com <tt>The bar chart and performance table below are intended to provide some<br />indication of the risks of investing in the fund by showing changes in the<br />fund's performance over time.<br />&#xA0;&#xA0;<br />The fund's past performance does not necessarily indicate how the fund will<br />perform in the future. Updated performance is available at mfs.com or by calling<br />1-800-225-2606.</tt> <tt>This table describes the fees and expenses that you may pay when you buy and<br />hold shares of the fund.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002435Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002435Member 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/ShareholderFeesData_S000002435Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> MCMXX 0.0124 lowest quarterly return highest quarterly return 0.00 2012-09-30 Returns Before Taxes Shares, At Net Asset Value 65 2006-12-31 205 0.0000 0.0100 0.0000 798 357 0.0508 0.0128 0.0000 0.0024 0.0230 0.0040 2011-12-31 0.0003 0.0146 0.0291 The total return for the nine-month period ended 0.0000 0.0060 0.0178 0.0064 0.0483 0.0000 0.00 <tt>The fund pays transaction costs, such as commissions, when it buys and sells<br />securities (or "turns over" its portfolio). A higher portfolio turnover rate may<br />indicate higher transaction costs and may result in higher taxes when shares are<br />held in a taxable account. These transaction costs, which are not reflected in<br />"Annual Fund Operating Expenses" or in the "Example," affect the fund's performance.&#xA0;&#xA0;<br />During the most recent fiscal year, the fund's portfolio turnover rate was 63% of <br />the average value of its portfolio.</tt> <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002434Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002434Member 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<br />with the cost of investing in other mutual funds.<br />&#xA0;&#xA0;<br />The example assumes that: you invest $10,000 in the fund for the time periods<br />indicated and you redeem your shares at the end of the time periods (unless<br />otherwise indicated); your investment has a 5% return each year; and the fund's<br />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)<br />normally invests at least 80% of the fund's net assets in issuers with medium<br />market capitalizations. MFS generally defines medium market capitalization<br />issuers as issuers with market capitalizations similar to those of issuers<br />included in the Russell Midcap&#xAE; Growth Index over the last 13 months at the <br />time of purchase. As of November 30, 2012, the range of the Russell Midcap&#xAE; <br />Growth Index was between $67.9 million and $19.8 billion.<br /> <br />MFS normally invests the fund's assets primarily in equity securities. Equity<br />securities include common stocks, preferred stocks, securities convertible into<br />stocks, and depositary receipts for such securities.<br />&#xA0;&#xA0;<br />MFS focuses on investing the fund's assets in the stocks of companies it<br />believes to have above average earnings growth potential compared to other<br />companies (growth companies).<br />&#xA0;&#xA0;<br />MFS may invest the fund's assets in foreign securities.<br />&#xA0;&#xA0;<br />MFS uses a bottom-up investment approach to buying and selling investments for<br />the fund. Investments are selected primarily based on fundamental analysis of<br />individual issuers. Quantitative models that systematically evaluate issuers may<br />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: 0.63 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<br />marginal income tax rates and do not reflect the impact of state and local taxes. <br />Your actual after-tax returns will depend on your own tax situation, and may differ <br />from those shown. The after-tax returns shown are not relevant to investors who <br />hold their shares through tax-deferred arrangements, such as 401(k) plans or <br />individual retirement accounts. The after-tax returns are shown for only one <br />of the fund's classes of shares, and after-tax returns for the fund's other <br />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 nine-month period ended September 30, 2012 was 14.20%.<br />During the period(s) shown in the bar chart, the highest quarterly return was<br />18.94% (for the calendar quarter ended September 30, 2009) and the lowest<br />quarterly return was (34.81)% (for the calendar quarter ended December 31,<br />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 <br />may be required to pay upon purchase or redemption of the fund's shares. If <br />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<br />lose money on your investment in the fund. An investment in the fund is not a<br />bank deposit and is not insured or guaranteed by the Federal Deposit Insurance<br />Corporation or any other governmental agency.<br />&#xA0;&#xA0;<br />The principal risks of investing in the fund are:<br />&#xA0;&#xA0;<br />Stock Market/Company Risk: Stock markets are volatile and can decline<br />significantly in response to issuer, market, economic, industry, political,<br />regulatory, geopolitical, and other conditions, as well as to investor<br />perceptions of these conditions. The price of an equity security can decrease<br />significantly in response to these conditions, and these conditions can affect <br />a single issuer or type of security, issuers within a broad market sector,<br />industry or geographic region, or the market in general.<br />&#xA0;&#xA0;<br />Growth Company Risk: The stocks of growth companies can be more sensitive to<br />the company's earnings and more volatile than the market in general.<br />&#xA0;&#xA0;<br />Mid Cap Risk: The stocks of mid cap companies can be more volatile than stocks<br />of larger companies.<br />&#xA0;&#xA0;<br />Foreign Risk: Exposure to foreign markets through issuers or currencies can<br />involve additional risks relating to market, economic, political, regulatory,<br />geopolitical, and other conditions. These factors can make foreign investments,<br />especially those in emerging markets, more volatile and less liquid than U.S.<br />investments. In addition, foreign markets can react differently to these<br />conditions than the U.S. market.<br />&#xA0;&#xA0;<br />Investment Selection Risk: MFS' investment analysis and its selection of<br />investments may not produce the intended results and/or can lead to an<br />investment focus that results in the fund underperforming other funds with<br />similar investment strategies and/or underperforming the markets in which the<br />fund invests.<br />&#xA0;&#xA0;<br />Liquidity Risk: It may not be possible to sell certain investments, types of<br />investments, and/or segments of the market at any particular time or at an<br />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<br />indication of the risks of investing in the fund by showing changes in the<br />fund's performance over time and how the fund's performance over time compares<br />with that of a broad measure of market performance.<br /> <br />The fund's past performance (before and after taxes) does not necessarily<br />indicate how the fund will perform in the future. Updated performance is<br />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<br />hold shares of the fund. Expenses for Class A, Class B, Class C, Class I,<br />Class 529A, Class 529B, Class 529C, Class R1, Class R2, Class R3, and Class R4<br />shares have been adjusted to reflect current fee arrangements. The annual fund<br />operating expenses for Class R5 shares are based on estimated "Other Expenses"<br />for the current fiscal year expressed as a percentage of the fund's estimated<br />average net assets during the period.<br />&#xA0;&#xA0;<br />You may qualify for sales charge reductions if you and certain members of your<br />family invest, or agree to invest in the future, at least $50,000 in MFS Funds.<br />More information about these and other waivers and reductions is available from<br />your financial intermediary and in "Sales Charges and Waivers or Reductions" on<br />page 7 of the fund's prospectus and "Waivers of Sales Charges" on page I-14 of<br />the fund's statement of additional information Part I.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002434Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002434Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * column rr_PerformanceMeasureAxis 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_S000002434Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/ShareholderFeesData_S000002434Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Index Comparison (Reflects no deduction for fees, expenses or taxes) Russell Midcap Growth Index -0.0165 0.0244 0.0529 A Shares Returns After Taxes on Distributions and Sale of Fund Shares -0.0749 -0.0244 -0.0238 A Shares Returns After Taxes on Distributions -0.1152 -0.0290 -0.0288 OTCKX 0.0000 R5 Shares Returns Before Taxes 97 307 -0.0002 1188 <tt>R5</tt> 534 -0.0585 0.0022 0.0075 -0.0149 0.0000 0.0201 0.0095 0.0097 <tt>Class R5 Shares</tt> <tt> ALL R</tt> 0.0000 OTCHX 0.0000 R3 Shares Returns Before Taxes 132 418 -0.0003 1599 <tt>R3</tt> 726 -0.0615 0.0033 0.0075 -0.0177 0.0025 0.0234 0.0130 0.0133 <tt>Class R3 Shares</tt> <tt> ALL R</tt> 0.0000 MCPRX 0.0000 R2 Shares Returns Before Taxes 158 496 -0.0003 1876 <tt>R2</tt> 858 -0.0629 0.0033 0.0075 -0.0201 0.0050 0.0262 0.0155 0.0158 <tt>Class R2 Shares</tt> <tt> ALL R</tt> 0.0000 OTCGX 0.0000 R1 Shares Returns Before Taxes 208 649 -0.0003 2408 <tt>R1</tt> 1116 -0.0684 0.0033 0.0075 -0.0251 0.0100 0.0308 0.0205 0.0208 <tt>Class R1 Shares</tt> <tt> ALL R</tt> 0.0000 OTCIX 0.0000 I Shares Returns Before Taxes 107 340 -0.0003 1314 <tt>I</tt> 593 -0.0585 0.0033 0.0075 -0.0149 0.0000 0.0201 0.0105 0.0108 <tt>Class I Shares</tt> <tt>I</tt> 0.0000 OTCCX 0.0000 C Shares Returns Before Taxes 308 208 649 -0.0003 2408 <tt>C</tt> 1116 -0.0779 0.0033 0.0075 2408 -0.0248 649 1116 <tt>Class C Shares assuming no redemption at end of period</tt> 0.0100 0.0299 0.0205 0.0208 <tt>Class C Shares assuming redemption at end of period</tt> <tt>C</tt> 0.0100 OTCBX 0.0000 B Shares Returns Before Taxes 608 208 949 -0.0003 2216 <tt>B</tt> 1316 -0.1055 0.0033 0.0075 2216 -0.0287 649 1116 <tt>Class B Shares assuming no redemption at end of period</tt> 0.0100 0.0282 0.0205 0.0208 <tt>Class B Shares assuming redemption at end of period</tt> <tt>B</tt> 0.0400 ECGRX 0.0000 529C Shares Returns Before Taxes 313 213 674 -0.0008 2507 <tt>529C</tt> 1162 -0.0789 0.0043 0.0075 2013-12-31 2507 -0.0261 674 1162 <tt>Class 529C Shares assuming no redemption at end of period</tt> 0.0100 0.0317 0.0210 0.0218 <tt>Class 529C Shares assuming redemption at end of period</tt> <tt>529C</tt> 0.0100 EBCGX 0.0000 529B Shares Returns Before Taxes 613 213 974 -0.0008 2317 <tt>529B</tt> 1362 -0.1053 0.0043 0.0075 2013-12-31 2317 -0.0297 674 1162 <tt>Class 529B Shares assuming no redemption at end of period</tt> 0.0100 0.0303 0.0210 0.0218 <tt>Class 529B Shares assuming redemption at end of period</tt> <tt>529B</tt> 0.0400 EAMCX 0.0575 529A Shares Returns Before Taxes 705 994 -0.0008 2183 <tt>529A</tt> 1305 -0.1164 0.0043 0.0075 2013-12-31 -0.0309 0.0025 0.0308 0.0135 0.0143 <tt>Class 529A Shares</tt> <tt>529A</tt> 0.0000 OTCJX 0.0000 R4 Shares Returns Before Taxes 107 340 -0.0003 1314 <tt>R4</tt> 593 -0.0585 0.0033 0.0075 -0.0154 0.0000 0.0209 0.0105 0.0108 <tt>Class R4 Shares</tt> <tt> ALL R</tt> 0.0000 OTCAX -0.4752 lowest quarterly return highest quarterly return 0.0575 2012-09-30 A Shares Returns Before Taxes 700 2009-09-30 969 -0.3481 0.1447 -0.0003 0.2869 2082 <tt>A</tt> 1259 0.0949 0.1894 -0.1152 0.0033 -0.5112 0.0075 2008-12-31 0.4163 -0.0290 0.0268 The total return for the nine-month period ended -0.0612 0.3799 0.0025 0.0283 0.0130 0.0133 0.0218 <tt>Class A Shares</tt> 0.1420 <tt>A</tt> 0.0100 <div style="display:none">~ http://www.mfs.com/role/ExpenseExample_S000002433Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/BarChartData_S000002433Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>The fund's investment objective is to seek current income consistent with<br />preservation of capital and liquidity.</tt> <tt>This example is intended to help you compare the cost of investing in the fund<br />with the cost of investing in other mutual funds.<br />&#xA0;&#xA0;<br />The example assumes that: you invest $10,000 in the fund for the time periods<br />indicated and you redeem your shares at the end of the time periods; your<br />investment has a 5% return each year; and the fund's operating expenses remain<br />the same.</tt> Performance Table. <tt>MFS (Massachusetts Financial Services Company, the fund's investment adviser)<br />normally invests at least 80% of the fund's net assets in U.S. Government money<br />market instruments and repurchase agreements collateralized by U.S. Government<br />securities.<br />&#xA0;&#xA0;<br />In buying and selling investments for the fund, MFS seeks to comply with<br />Securities and Exchange Commission rules for money market funds regarding credit<br />quality, diversification, liquidity, and maturity. MFS stresses maintaining a<br />stable $1.00 share price, liquidity, and income.</tt> Summary of Key Information Example Investment Objective The fund's past performance does not necessarily indicate how the fund will perform in the future. 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: Bar Chart. Performance Information 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. <tt>The total return for the nine-month period ended September 30, 2012 was 0.00%.<br />During the period(s) shown in the bar chart, the highest quarterly return was<br />1.19% (for the calendar quarter ended June 30, 2007) and the lowest quarterly<br />return was 0.00% (for the calendar quarter ended March 31, 2009, quarter ended<br />June 30, 2009, quarter ended September 30, 2009, quarter ended March 31, 2010,<br />quarter ended June 30, 2010, quarter ended September 30, 2010, quarter ended<br />December 31, 2010, quarter ended March 31, 2011, quarter ended June 30, 2011,<br />quarter ended September 30, 2011, and the quarter ended December 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) Although the fund seeks to preserve the value of your investment at $1.00 per share, the fund may not achieve its objective and you could lose money on your investment in the fund. <tt>Although the fund seeks to preserve the value of your investment at $1.00 per<br />share, the fund may not achieve its objective and you could lose money on your<br />investment in the fund. An investment in the fund is not a bank deposit and is<br />not insured or guaranteed by the Federal Deposit Insurance Corporation or any<br />other governmental agency.<br />&#xA0;&#xA0;<br />The principal risks of investing in the fund are:<br />&#xA0;&#xA0;<br />Interest Rate, Credit, and Liquidity Risk:&#xA0;&#xA0;Although MFS seeks to maintain a<br />stable $1.00 share price for the fund, there is no guarantee that it will be<br />able to do so. A major increase in interest rates or a decline in the credit<br />quality of an issuer or entity providing credit support, an inactive trading<br />market for money market instruments, or adverse market, economic, political,<br />regulatory, geopolitical, and other conditions could cause the fund's share<br />price to decrease to below $1.00.<br />&#xA0;&#xA0;<br />Investment Selection Risk: MFS' investment analysis and its selection of<br />investments may not produce the intended results and/or can lead to an<br />investment focus that results in the fund underperforming other funds with<br />similar investment strategies and/or underperforming the markets in which the<br />fund invests.<br />&#xA0;&#xA0;<br />Counterparty and Third Party Risk: Transactions involving a counterparty or<br />third party other than the issuer of the instrument are subject to the credit<br />risk of the counterparty or third party, and to the counterparty's or third<br />party's ability to perform in accordance with the terms of the transaction.<br />&#xA0;&#xA0;<br />Liquidity Risk: It may not be possible to sell certain investments, types of<br />investments, and/or segments of the market at any particular time or at an<br />acceptable price.</tt> Fees and Expenses Principal Investment Strategies <tt>The bar chart and performance table below are intended to provide some<br />indication of the risks of investing in the fund by showing changes in the<br />fund's performance over time.<br />&#xA0;&#xA0;<br />The fund's past performance does not necessarily indicate how the fund will<br />perform in the future. Updated performance is available at mfs.com or by calling<br />1-800-225-2606.</tt> <tt>This table describes the fees and expenses that you may pay when you buy and<br />hold shares of the fund.</tt> <div style="display:none">~ http://www.mfs.com/role/OperatingExpensesData_S000002433Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.mfs.com/role/PerformanceTableData_S000002433Member 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/ShareholderFeesData_S000002433Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> MMGXX 0.0113 lowest quarterly return highest quarterly return 0.00 2012-09-30 Returns Before Taxes Shares, At Net Asset Value 115 2007-06-30 359 0.0000 0.0090 0.0000 1375 622 0.0465 0.0119 0.0000 0.0073 0.0168 0.0040 2011-12-31 0.0001 0.0125 0.0265 The total return for the nine-month period ended 0.0000 0.0048 0.0157 0.0113 0.0438 0.0000 0.00 0000063068 ck0000063068:SummaryS000002433Memberck0000063068:S000002433Memberck0000063068:C000006503Member 2012-12-29 2012-12-29 0000063068 ck0000063068:SummaryS000002433Memberck0000063068:S000002433Member 2012-12-29 2012-12-29 0000063068 ck0000063068:SummaryS000002434Memberck0000063068:S000002434Memberck0000063068:C000006504Member 2012-12-29 2012-12-29 0000063068 ck0000063068:SummaryS000002434Memberck0000063068:S000002434Memberck0000063068:C000006505Member 2012-12-29 2012-12-29 0000063068 ck0000063068:SummaryS000002434Memberck0000063068:S000002434Memberck0000063068:C000006506Member 2012-12-29 2012-12-29 0000063068 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MFS Fund Distributors, Inc. has agreed in writing to waive the program management fee for each of the fund's Class 529A, Class 529B, and Class 529C shares to 0.05% of the fund's average daily net assets attributable to each share class annually. This written agreement will expire on December 31, 2013, unless MFS Fund Distributors, Inc. elects to extend the waiver. In addition, effective January 1, 2013, Massachusetts Financial Services Company has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 1.30% of the fund's average daily net assets annually for each of Class A and Class R3 shares, 2.05% of the fund's average daily net assets annually for each of Class B, Class C, and Class R1 shares, 1.05% of the fund's average daily net assets annually for each of Class I and Class R4 shares, 1.35% of the fund's average daily net assets annually for Class 529A shares, 2.10% of the fund's average daily net assets annually for each of Class 529B and Class 529C shares, 1.55% of the fund's average daily net assets annually for Class R2 shares, and 0.95% of the fund's average daily net assets annually for Class R5 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least December 31, 2013. Massachusetts Financial Services Company has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 1.50% of the fund's average daily net assets annually for each of Class A and Class R3 shares, 2.25% of the fund's average daily net assets annually for each of Class B, Class C, and Class R1 shares, 1.25% of the fund's average daily net assets annually for each of Class I, Class R4, and Class R5 shares, and 1.75% of the fund's average daily net assets annually for Class R2 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least December 31, 2013.