Designers own the rights to their design submissions until the contest holder chooses one of the designs as the contest’s winner. Then the designer transfers their rights in the Design Handover stage, and once it’s done, the contest holder becomes owner of the rights to that particular design.
If a designer creates several design concepts for one contest, but the contest holder only buys one of them, then all the unused design concepts remain the property of the designer. The contest holder can always buy the other designs.
If the contest holder does not select a winner or buys a designer’s design, it remains the property of the designer.