Is it permissible to act as an intermediary in selling a property to an interest-based bank?

It is not permissible to mediate in the sale of a property to a usurious bank if the mediator knows that the property will be taken as its headquarters, or that the sale of the property is part of a forbidden usurious transaction. However, if it is for other than that, then there is no harm in mediating. It is better for a Muslim to avoid dealing with usurious banks as much as possible.