Capstead Mortgage Corporation, formed in 1985 and based in Dallas, Texas, is a self-managed real estate investment trust for federal income tax purposes. Capstead's core investment strategy is managing a leveraged portfolio of residential mortgage pass-through securities consisting almost exclusively of ARM securities issued and guaranteed by government-sponsored entities, either Fannie Mae or Freddie Mac, or by an agency of the federal government, Ginnie Mae. Agency-guaranteed residential mortgage securities carry an implied AAA credit rating with limited, if any, credit risk.