A Master Bill of Lading (MBL) is the bill of lading issued by the actual ocean carrier (the vessel-operating common carrier, or VOCC) to the party that booked the space — typically an NVOCC or freight forwarder acting as consolidator.
The MBL covers the entire container or vessel-level booking. On the document, the shipper is the NVOCC at origin and the consignee is its agent or affiliate at destination — the actual cargo owners do not appear on the MBL at all.
The NVOCC then issues separate House Bills of Lading to each underlying customer whose goods are inside the container.
The MBL/HBL split matters because:
- Customs — CBP receives the MBL data via the carrier's AMS filing; HBL data is filed separately by the NVOCC.
- Cargo release — the carrier releases the container against the MBL; the NVOCC releases individual lots against the HBLs.
- Liability — the carrier's COGSA limit attaches to the MBL relationship; the NVOCC's tariff governs the HBL relationship.
For FCL direct bookings with no consolidator in the middle, there is no separate house bill — the carrier's BOL is the only document, and it functions as both.