The investment seeks total return with an emphasis on high current income, but also considering capital appreciation. MFS normally invests the fund's assets primarily in a broad range of debt instruments issued by U.S. and foreign corporate, government, and other entities, including below investment grade quality debt instruments and debt instruments of issuers located in emerging market countries. MFS focuses on investing the fund's assets in corporate bonds, mortgage-backed securities and other securitized instruments, U.S. government securities, and debt instruments of issuers located in emerging market countries.