SL Green Realty (NYSE: SLG) is a real estate investment trust (REIT), a corporate structure designed to invest properties and to pass on most of its taxable income to shareholders. Historically speaking, office REITs have had modest payout ratios because of this. As an example, every time a tenant vacates a space, landlords like SL Green have to look for a new tenant and (here's the expensive part) provide improvements to the location to get the new tenant in the door.