shop right, in united states patent law, is an implied license under which a firm may use a patented invention, invented by an employee who was working within the scope of their employment, using the firms' equipment, or inventing at the firms' expense. even if the employee never assigned rights to the firm, a court of law may find that the firm has the right to make use of the invention, and thus can not be sued by the employee for patent infringement. this will allow the firm to attempt to capitalize on the value of the patent, as the firm is allowed to use the object of the patent in the routine operation of its business without royalty payments. shop right is non-transferable. it only inures to the benefit of the employer and can not be sold by that employer to an unrelated party, except in a sale of the business as a whole.