Western Asset Mortgage Defined Opportunity Fund Inc. (the Fund) is a non-diversified, limited-term, closed-end management investment company. The Fund's primary investment objective is to provide current income. The Fund seeks to achieve its investment objective by investing primarily in a diverse portfolio of mortgage-backed securities (MBS), consisting primarily of non-agency residential mortgage-backed securities (RMBS) and commercial mortgage-backed securities (CMBS). The Fund invested in MBS directly, and indirectly through a separate investment in a public-private investment fund (PPIF) (Master Fund) formed in connection with the Legacy Securities Public-Private Investment Program (PPIP) established by the United States Department of the Treasury (Treasury). Legg Mason Partners Fund Advisor, LLC (LMPFA) is the Fund's investment manager. Western Asset Management Company (Western Asset) and Western Asset Limited (Western Asset Limited) are the Fund's subadvisers.