Nemo dat quod non habet, literally meaning "no one can give what they do not have", is a legal rule, sometimes called the nemo dat rule, that states that the purchase of a possession from someone who has no ownership right to it also denies the purchaser any ownership title.
It is equivalent to the civil (continental) Nemo plus iuris ad alium transferre potest quam ipse habet rule, which means "one cannot transfer to another more rights than they have".
However, the problem of successive bona fide purchasers can be remedied: If the jurisdiction recognises an implied warranty that the seller has title to the property (such as under Article 2 of the Uniform Commercial Code (UCC)), then the bona fide purchaser can sue the seller for breach of that implied warranty.
Courts of equity traditionally also recognise various other exceptions, likely giving rise to the idea embodied in the modern UCC.
This rule is exemplified in circumstances like the Holocaust reconciliation movement, where property, such as works of art, stolen or confiscated by the Nazis was returned to the families of the original owners.
Anyone who purchased the art or thought they had ownership was denied any rights over the litigious property due to the nemo dat rule.