When a real estate investment trust (REIT) trades below book value, it’s in the bargain basement of stock market offerings. When that REIT offers a dividend, the investor receives payment just for holding the cheap security. It can be a sweet combination of factors — as long as other important metrics align favorably. Here are four REITs that seem to fit that bill: New York-based Blackstone Mortgage Trust Inc. (NYSE: BXMT) is a mortgage REIT. As the company puts it on its website, Blackstone “is