A system for using real estate lease data has at least one property file stored on a data storage device and representing a property that has at least one leasable space, and a lease deal component operated by at least one processor and receiving data for a plurality of lease deals each with terms of a lease deal. At least one previously established lease deal has data for a lease deal, and is associated to at least one leasable space. This lease deal was established previously to at least one subsequent lease deal. The lease deal component links at least one subsequent lease deal to the at least one previously established lease deal to associate the at least one subsequent lease deal with an amount of leasable space linked to the previously established lease deal. A display displays lease terms or results of financial calculations or both of at least one linked lease deal.