In the context of Intellectual Property Rights, what is the key distinction between "Assignment" and "Licensing" of IP rights?

Assignment of an IP right involves the complete transfer of ownership from the assignor (original IP owner) to the assignee after assignment, the assignee becomes the new owner with all rights, and the original owner loses all rights in the IP. In contrast, Licensing is a contractual arrangement where the IP owner (licensor) grants another party (licensee) permission to use the IP without transferring ownership the licensor retains title and can grant multiple licences to different parties. Licences can be exclusive (only one licensee, even excluding the licensor), sole (licensor and one licensee only), or non-exclusive (multiple licensees simultaneously). Under the Patents Act, 1970, assignment must be in writing signed by both parties, and to be effective against third parties, must be registered with the Controller of Patents. Licensing is often commercially preferred over assignment because it allows the IP owner to retain control, receive ongoing royalties, and exploit the IP in multiple markets simultaneously. Assignment is generally considered an outright sale of IP, while licensing is akin to a rental or lease arrangement.