A “holding deposit” is a sum of money paid by a potential tenant to a rental property owner to ensure that the property is not leased to someone else for a specific amount of time. For example, a landlord may ask you for a deposit to “hold” an apartment or house—i.e., not rent it to others—while you decide whether you do in fact want to rent the property.
Holding deposits are designed to give potential tenants an opportunity to determine whether they would like to or are able to lease certain property. The holding deposit serves to compensate the owner if the potential tenant decides not to lease the property. In theory, a property owner should only retain the amount of a holding deposit equivalent to the actual damages caused by a potential tenant not signing a lease contract. The owner should return the remainder of the deposit to the tenant.
students.ucsd.edu/_files/sls/handbook/SLSHandbook-LandlordTenant1.pdf