They are "guaranteeing" in that they are putting themselves in high but limited liability in case they can't fulfill that "guarantee". As long as they can find

They are "guaranteeing" in that they are putting themselves in high but limited liability in case they can't fulfill that "guarantee". As long as they can find tenants for at least 6/7 (~85%) of their apartments, they're breaking even. Clearly, they think that's an easy target to hit. (Another way to think of it: one service they provide is amortization of the risk of not filling the apartment over their entire catalog of apartments.)