• A third-party logistics provider, sometimes called a 3PL or 3PL company, is a firm that provides outsourced logistics services to client companies for part, or all of their supply chain management functions.
• Every 3PL company is different. For us (ProPack), this involves warehousing products, fulfilling orders, and forwarding freight (northbound and southbound), all while keeping our clients thoroughly up to date on the status of their goods.
• The term "3PL" was first used in the early 1970s to identify intermodal marketing companies (IMCs) in transportation contracts. Up to that point, contracts for transportation had featured only two parties, the shipper and the carrier.
• When IMCs entered the picture—as intermediaries that accepted shipments from the shippers and tendered them to the rail carriers—they became the third party to the contract, the 3PL.
• Definition has broadened to the point where these days, every company that offers some kind of logistics service for hire calls itself a 3PL. preferably, these services are integrated, or “bundled,” together by the provider. Services they provide are transportation, warehousing, cross-docking, inventory management, packaging, and freight forwarding.
• “A person who solely receives, holds, or otherwise transports a consumer product in the ordinary course of business but who does not take title to the product.”

Differs from third party logistics in the following ways;

a) 4PL organization is often a separate entity established as a joint venture or long-term contract between a primary client and one or more partners;

b) 4PL organization acts as a single interface between the client and multiple logistics service providers; All aspects (ideally) of the client’s supply chain are managed by the 4PL organization; and,

c) It is possible for a major third-party logistics provider to form a 4PL organization within its existing structure. "A supply chain integrator that assembles and manages the resources, capabilities, and technology of its own organization with those of complementary service providers to deliver a comprehensive supply chain solution.", but is no longer registered.

4PLs have also been referred to as "Lead Logistics Providers". Now a new crop of companies have emerged who are actual transportation companies too. While a 4PL is sometimes described as non-asset-owning service provider, their role is to provide broader scope managing of the entire supply chain.