Assignment, in law, the making over or transferring of any species of property. It also signifies the deed or instrument by which the transfer is operated. The assignment of a lease is the transfer of the assignor's whole estate in the term created by the original lease. The difference between an assignment and an underlease is that the underlease retains the reversion, whereas the assignment parts with it. Assignment in commercial law was formerly much restricted. Bills of lading and bills of exchange were not assignable. All interests in personal property, of which a man has not the actual possession, but merely the right to recover, are choses in action. Thus a debt, whether specialty or simple contract, is a chose in action, a something to be recovered. These were not assignable. These restraints were, however, evaded by a license to use the name of the legal creditor. Even under a bill of sale of goods, the property in them does not pass unless by actual delivery and possession as against hona fide creditors.

Both by the English and French law, property in the power and disposition of a debtor may by process of law be transferred to his creditor.