Western Asset Mortgage Defined Opportunity Fund Inc. is a closed ended fixed income mutual fund launched and managed by Legg Mason Partners Fund Advisor, LLC. The fund is co-managed Western Asset Management Company and Western Asset Management Company Limited. It invests in the fixed income markets of the United States. The fund invests primarily in mortgage-backed securities. It employs intensive proprietary research to create its portfolio. The fund benchmarks the performance of its portfolio against the BofA Merrill Lynch U.S. Floating Rate Home Equity Loan Asset Backed Securities Index. Western Asset Mortgage Defined Opportunity Fund Inc. was formed on December 11, 2009 and is domiciled in the United States.