Strategy. 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 funds investment adviser), referred to as underlying funds. MFS selects the asset class allocations based on a strategic asset allocation process that takes into account a variety of factors, including historical risk and performance, projected performance, and other factors. MFS analyses of projected performance are primarily based on quantitative models using various inputs such as valuation metrics, growth rates, profitability, yields, and inflation. MFS may also consider current market conditions, its qualitative assessment of the risk/return characteristics of asset classes, and other factors in determining these allocations. MFS employs the strategic asset allocation … Show more… 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 funds investment adviser), referred to as underlying funds. MFS selects the asset class allocations based on a strategic asset allocation process that takes into account a variety of factors, including historical risk and performance, projected performance, and other factors. MFS analyses of projected performance are primarily based on quantitative models using various inputs such as valuation metrics, growth rates, profitability, yields, and inflation. MFS may also consider current market conditions, its qualitative assessment of the risk/return characteristics of asset classes, and other factors in determining these allocations. MFS employs the strategic asset allocation process described above to determine the amount of the fund's assets invested in (1) underlying funds that invest primarily in equity securities (Equity Funds) and underlying funds that provide exposure to less traditional asset classes, such as real estate and commodities (Non-Traditional Funds) and (2) underlying funds that invest primarily in debt instruments (Bond Funds) and an underlying fund that invests in cash and/or cash equivalents (Money Market Fund). MFS selects the underlying funds within each asset class based on underlying fund classifications, historical risk, historical and projected performance of the represented asset classes, as well as other factors. Within the Equity Fund allocation, MFS seeks to diversify by geography (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). A portion of the funds assets is also allocated to Non-Traditional Funds (i.e., asset classes less correlated to the overall equity and debt markets), which MFS believes provides further diversification benefits. Within the Bond Fund allocation, MFS includes underlying funds with varying degrees of geographic, interest rate, and credit exposure as potential investments for the fund, including exposure to below investment grade quality debt instruments. A portion of the funds assets may also be allocated to the Money Market Fund. MFS normally invests the underlying funds assets across different industries, sectors, countries, and regions, but MFS may invest a significant percentage of the underlying funds' assets in issuers in a single industry, sector, country, or region. As of September 1, 2025, the funds approximate long-term strategic allocation among asset classes was: Equity Funds and Non-Traditional Funds 100% Bond Funds and Money Market Fund 0% All percentages are rounded to the nearest percent. MFS may deviate from the long-term strategic allocations set forth above; however, any deviation from the long-term strategic allocation is not expected to be greater than plus or minus 10% under normal market conditions. Additionally, the funds allocation to Non-Traditional Funds will not typically exceed 20% of the funds assets. As of September 1, 2025, the funds approximate strategic allocation among asset classes was: Equity Funds and Non-Traditional Funds 99.0% U.S. Equity Funds 58.5% International Equity Funds 30.5% Non-Traditional Funds 10.0% Bond Funds and Money Market Fund 1.0% Bond Funds 0.0% Money Market Fund 1.0% All percentages are rounded to the nearest tenth of a percent. As a result, the sum of the asset class allocations presented in the table may not total 100%. Show less