A REIT, or real estate investment trust, is a company that invests in real estate ventures, such as shopping malls, apartment and office buildings, and hotels, and then packages interest in the real estate properties to sell as a security. REITs provide revenue to investors through the rental and/or mortgage payments made on the properties and sales of the properties. Many REITS are private placements and are not traded on the open market, meaning they bear a high level of risk and illiquidity.