Arrangement in which a firm contracts out (outsources) its logistical operations to two or more specialist firms (the third party logistics) and hires another specialist firm (the fourth party) to coordinate the activities of the third parties.
A 4PL is an integrator that assembles the resources, capabilities, and technology of its own organization and other organizations to design, supply chain solutions. A 4PL uses a 3PL to supply service to customers, owning only computer systems and intellectual capital.
It has been argued that a 4PL is the same thing as a "Non Asset-Based 3PL".