Capstead Mortgage Corporation operates as a real estate investment trust (REIT) in the United States. It invests in a portfolio of residential mortgage pass-through securities primarily consisting of short-duration adjustable-rate mortgage securities issued and guaranteed by government-sponsored enterprises, or by an agency of the federal government. The company qualifies as a REIT for federal income tax purposes. It generally would not be subject to federal corporate income taxes if it distributes at least 90% of its taxable income to its stockholders. The company was incorporated in 1985 and is headquartered in Dallas, Texas.