MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in debt instruments. Debt instruments include U.S. Government securities, corporate debt instruments, foreign government securities, securitized instruments (including mortgage-backed securities and other asset-backed securities), and other obligations to repay money borrowed.

In managing the fund, MFS employs a short duration investment strategy whereby the dollar-weighted average effective duration of the fund’s portfolio will approximate that of the Bloomberg 1-5 Year Government/Credit Bond Index plus or minus 1 year. Duration is a measure of a debt instrument’s or a portfolio of debt instruments’ sensitivity to a change in interest rates expressed in years. For example, if a debt instrument has a 3-year duration and interest rates rise 1%, the debt instrument’s value is likely to fall approximately 3%.

MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments.

MFS invests the fund’s assets in U.S. securities and U.S. dollar-denominated foreign securities, which may include emerging market securities.

MFS normally invests the fund's assets across different industries, sectors, countries, and regions, but MFS may invest a significant percentage of the fund’s assets in issuers in a single industry, sector, country, or region.

MFS may invest a significant 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 exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, and swaps.

MFS uses an active 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 screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.

MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. MFS defines municipal instruments as debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds.

MFS normally invests at least 80% of the fund’s net assets in municipal instruments, the interest on which is exempt from U.S. federal income tax. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax.

In managing the fund, MFS employs a short duration investment strategy whereby the dollar-weighted average effective duration of the fund’s portfolio will not normally exceed three years. Duration is a measure of a debt instrument’s or a portfolio of debt instruments’ sensitivity to a change in interest rates expressed in years. For example, if a debt instrument has a 3-year duration and interest rates rise 1%, the debt instrument’s value is likely to fall approximately 3%.

MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments.

MFS may invest 25% or more of the fund’s total assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water, or sewers.

MFS may invest a significant percentage of the fund's assets in issuers in a single state, territory, or possession, or a small number of states, territories, or possessions.

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 exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.

MFS uses an active 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 screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.

For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.