ARMOUR Residential REIT Inc is a real estate investment trust that invests in residential mortgage-backed securities or RMBS. These are issued or guaranteed by U.S.-government-sponsored enterprises, such as Fannie Mae, Freddie Mac, or Ginnie Mae. The company's investment portfolio is composed of mortgage-backed securities, adjustable-rate mortgage securities, and multifamily mortgage-backed securities. In terms of total fair value, most Armour's investments are long-term, fixed-rate agency RMBS. Multifamily RMBS also represents a substantial amount. Fannie Mae guarantees most of the company's holdings. Armour derives substantially all its revenue as interest income from its investments.