Latin for ‘no one can give what they do not have’, nemo dat quod non habet is a legal maxim for the basic principle that a person who does not own property/has no title (i.e. a thief) cannot transfer its ownership/title validly to confer a better title on a third party without the true owner/title holder’s authority.
For example, if Jane and John are siblings, and Jane is named in her father’s will as the recipient of his car, John cannot validly sell the car on to a third party without Jane’s authority.
There are numerous common law and statutory exceptions to this rule, intending to give protection to bona fide purchasers and original owners.
The nemo dat quod non habet rule has now been subsumed into the Personal Properties Securities Act (2009) which is the authoritative source of law.