Depending on the type of property the rental yelds in central Tokyo go anywhere from 4% to 7% on new property. 

As for the construction company`s interest, I believe there must be some limits established regarding the maximum area and maximum number of units one can have, which we were not told of yet. The property still remains to be decided and distributed between the parties involved. How it will be done, and based on what criteria we have not been told yet.