MBL
A Master Bill of Lading (MBL) is the bill of lading issued by the actual ocean carrier (shipping line) to the freight forwarder, NVOCC, or shipper who booked the container space. The MBL covers the relationship between the shipping line and its direct customer.
When a freight forwarder or NVOCC consolidates multiple shippers into one container, they hold one MBL with the shipping line and issue multiple HBLs (House Bills of Lading) to the individual shippers. Modern freight platforms auto-reconcile each HBL to its parent MBL — flagging variances in weight, container count, freight terms or payment terms before customs filing.
The MBL is the document that controls the actual cargo release at destination — the shipping line will not release the container until the holder of the MBL (or their order) presents the original document.