MFS® Aggressive Growth Allocation Fund

MFS® Aggressive Growth Allocation Fund Summary of Key Information

Investment Objective

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 are MFS Conservative Allocation Fund, MFS Moderate Allocation Fund, MFS Growth Allocation Fund, and MFS Aggressive Growth Allocation Fund.)

Fees and Expenses

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

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 10 of the fund’s Prospectus and “Waivers of Sales Charges” on page H-1 of the fund’s Statement of Additional Information (“SAI”).

Shareholder Fees (fees paid directly from your investment):

Shareholder Fees - MFS® Aggressive Growth Allocation Fund	A		529A	B	529B	C	529C	I	R1	R2	R3	R4
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	5.75%		5.75%	none	none	none	none	none	none	none	none	none
Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, whichever is less)	1.00%	[1]	none	4.00%	4.00%	1.00%	1.00%	none	none	none	none	none

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses - MFS® Aggressive Growth Allocation Fund		A	B	C	I	529A	529B	529C	R1	R2	R3	R4
Management Fee		none	none	none	none	none	none	none	none	none	none	none
Distribution and/or Service (12b-1) Fees		0.25%	1.00%	1.00%	none	0.25%	1.00%	1.00%	1.00%	0.50%	0.25%	none
Other Expenses		0.15%	0.15%	0.15%	0.15%	0.25%	0.25%	0.25%	0.15%	0.15%	0.15%	0.15%
Acquired (Underlying) Fund Fees and Expenses		0.74%	0.74%	0.74%	0.74%	0.74%	0.74%	0.74%	0.74%	0.74%	0.74%	0.74%
Total Annual Fund Operating Expenses		1.14%	1.89%	1.89%	0.89%	1.24%	1.99%	1.99%	1.89%	1.39%	1.14%	0.89%
Fee Reductions and/or Expense Reimbursements	[1]	(0.02%)	(0.02%)	(0.02%)	(0.02%)	(0.07%)	(0.07%)	(0.07%)	(0.02%)	(0.02%)	(0.02%)	(0.02%)
Total Annual Fund Operating Expenses After Fee Reductions and/or Expense Reimbursements		1.12%	1.87%	1.87%	0.87%	1.17%	1.92%	1.92%	1.87%	1.37%	1.12%	0.87%

Example

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.

Although your actual costs will likely be higher or lower, under these assumptions your costs would be:

Expense Example - MFS® Aggressive Growth Allocation Fund - USD ($)	1 YEAR	3 YEARS	5 YEARS	10 YEARS
A	683	915	1,165	1,880
B	590	892	1,219	2,014
C	290	592	1,019	2,210
I	89	282	491	1,094
529A	687	939	1,210	1,983
529B	595	918	1,266	2,117
529C	295	618	1,066	2,311
R1	190	592	1,019	2,210
R2	139	438	759	1,667
R3	114	360	626	1,384
R4	89	282	491	1,094

Expense Example No Redemption - MFS® Aggressive Growth Allocation Fund - USD ($)	1 YEAR	3 YEARS	5 YEARS	10 YEARS
B	190	592	1,019	2,014
C	190	592	1,019	2,210
529B	195	618	1,066	2,117
529C	195	618	1,066	2,311

Portfolio Turnover

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 5% of the average value of its portfolio.

Principal Investment Strategies

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) based on the risk/return potential of the different asset classes and the risk profile of the fund. 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 1, 2016, the fund’s approximate target allocation among asset classes and the underlying funds was:

Bond Funds:	0.0	%
International Stock Funds:	30.0	%
MFS Emerging Markets Equity Fund	2.0	%
MFS International Growth Fund	8.0	%
MFS International New Discovery Fund	4.0	%
MFS International Value Fund	8.0	%
MFS Research International Fund	8.0	%
U.S. Stock Funds:	60.0	%
MFS Growth Fund	13.0	%
MFS Mid Cap Growth Fund	10.0	%
MFS Mid Cap Value Fund	10.0	%
MFS New Discovery Fund	2.5	%
MFS New Discovery Value Fund	2.5	%
MFS Research Fund	9.0	%
MFS Value Fund	13.0	%
Specialty Funds:	10.0	%
MFS Commodity Strategy Fund	5.0	%
MFS Global Real Estate Fund	5.0	%

All percentages are rounded to the nearest tenth of a percent.

Principal Risks

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:

Allocation Risk:  MFS’ assessment of the risk/return potential of asset classes and underlying funds, and the resulting allocation among 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.

Underlying Funds Risk:  MFS’ strategy of investing in underlying funds exposes the fund to the risks of the underlying funds. Each underlying fund pursues its own investment objective and strategies and may not achieve its objective.  In addition, shareholders of the fund will indirectly bear the fees and expenses of the underlying funds.

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.

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.

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 Risk:  Exposure to foreign markets through issuers or currencies can involve additional risks relating to market, economic, industry, political, regulatory, geopolitical, and 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 Risk:  Investments in emerging markets can involve additional and greater risks than the risks associated with investments in developed foreign markets.  Emerging markets can have less developed markets, greater custody and operational risk, 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, industry, political, regulatory, geopolitical, and 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.

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; difficulties in valuing and disposing of real estate; fluctuations in interest rates and property tax rates; shifts in 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; the management skill and creditworthiness of the real estate investment trust (REIT) manager; 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.

Commodity-Related Investments Risk:  The value of commodity-related investments may be more volatile than the value of equity securities or debt instruments and 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-related investment may be affected by demand/supply imbalances in the market for the commodity.

Industry and Sector Focus Risk:  Issuers in an industry or sector can react similarly to market, economic, political, regulatory, geopolitical, and other conditions.  If MFS invests a significant percentage of the fund’s assets in issuers within an industry or sector, the fund’s performance will be affected by conditions in that industry or sector.

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 or willingness to perform in accordance with the terms of the transaction.

Liquidity Risk:  It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at a price or time that is not advantageous in order to meet redemptions or other cash needs.

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.

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 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.

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.

Class A Bar Chart.

The total return for the six-month period ended June 30, 2016, was 3.78%. 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).

Performance Table.

Average Annual Total Returns (For the Periods Ended December 31, 2015)

Average Annual Returns - MFS® Aggressive Growth Allocation Fund	Label	Average Annual Returns, 1 Years	Average Annual Returns, 5 Years	Average Annual Returns, 10 Years
B	B Shares Returns Before Taxes	(4.66%)	6.66%	4.97%
C	C Shares Returns Before Taxes	(1.79%)	6.97%	4.82%
I	I Shares Returns Before Taxes	0.11%	8.03%	5.88%
529A	529A Shares Returns Before Taxes	(5.91%)	6.45%	4.84%
529B	529B Shares Returns Before Taxes	(4.72%)	6.59%	4.87%
529C	529C Shares Returns Before Taxes	(1.85%)	6.93%	4.71%
R1	R1 Shares Returns Before Taxes	(0.89%)	6.97%	4.80%
R2	R2 Shares Returns Before Taxes	(0.35%)	7.51%	5.32%
R3	R3 Shares Returns Before Taxes	(0.09%)	7.78%	5.58%
R4	R4 Shares Returns Before Taxes	0.16%	8.07%	5.86%
A	A Shares Returns Before Taxes	(5.88%)	6.50%	4.95%
After Taxes on Distributions | A	A Shares Returns After Taxes on Distributions	(6.98%)	6.03%	4.45%
After Taxes on Distributions and Sale of Fund Shares | A	A Shares Returns After Taxes on Distributions and Sale of Fund Shares	(2.39%)	5.09%	3.94%
Standard & Poor’s 500 Stock Index	Index Comparisons (Reflects no deduction for fees, expenses, or taxes) Standard & Poor's 500 Stock Index	1.38%	12.57%	7.31%
MFS Aggressive Growth Allocation Fund Blended Index	Index Comparisons (Reflects no deduction for fees, expenses, or taxes) MFS Aggressive Growth Allocation Fund Blended Index	(0.54%)	8.43%	5.56%

As of December 31, 2015, the MFS Aggressive Growth Allocation Fund Blended Index (the “Blended Index”) consisted of the following indices and weightings: 60% Standard & Poor’s 500 Stock Index; 30% MSCI EAFE (Europe, Australasia, Far East) Index; 5% Bloomberg Commodity Index; and 5% FTSE EPRA/NAREIT Developed Real Estate Index. The components and weightings of the Blended Index may have differed during the period, and may differ in the future.

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-advantaged 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.

[1] This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase.

[1] 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 class' average daily net assets attributable to each share class annually. This written agreement will expire on September 30, 2017, unless MFS Fund Distributors, Inc., elects to extend the waiver. Massachusetts Financial Services Company has agreed in writing to bear the fund's expenses, excluding program management fees, management fees, distribution and service fees, interest, taxes, extraordinary expenses, brokerage and transaction costs, and investment-related expenses, including fees and expenses associated with investments in investment companies and other similar investment vehicles, such that "Other Expenses" do not exceed 0.13% of the class' average daily net assets annually for each class of shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least September 30, 2017.