eBook lending licenses as brokered by the companies that provide this service to libraries (e.g. Overdrive) usually restrict the number of "copies" of an eBook

eBook lending licenses as brokered by the companies that provide this service to libraries (e.g. Overdrive) usually restrict the number of "copies" of an eBook that can be loaned at one time, and patrons often have to put themselves on waiting lists for books the same as they would have to for a checked out physical book. Obtaining additional available "copies" for popular eBooks is functionally the same as the library buying extra copies of a physical book.