REITs come in two varieties: equity REITs and mortgage REITs. Equity REITs aim to hold various kinds of real estate. Offices, hotels, shopping malls, and many other types of commercial property are included. An equity REIT's primary source of income is rent from these properties. The other is a mortgage REIT, which aims to fund both residential and commercial real estate. Their primary source of income is the interest they get on their investments in mortgages or mortgage-backed securities.