ARMOUR Residential REIT, Inc. invests in residential mortgage-backed securities (MBS) in the United States. Its securities portfolio primarily consists of the United States Government-sponsored entity's (GSE) and the Government National Mortgage Administration’s issued or guaranteed securities backed by fixed rate, hybrid adjustable rate, and adjustable-rate home loans; and unsecured notes and bonds issued by the GSE and the United States treasuries, as well as money market instruments. The company has elected to be taxed as a real estate investment trust.