The original 4PL was described as non-asset owning - i.e. it subcontracted the warehousing and distribution to 3PLs, hauliers etc. My understanding of a 4PL is a 3PL with a 4PL division. Hence 3 plus 4 = 7! These divisions may or may not use some of their own assets to undertake the work. I suppose technically they are lead logistics providers! I did come across one 3PL with a 4PL division who categorically stated they would not use their own assets under any circumstances even if it was cheaper for the customer! - What's the sense in that?!!