What is the difference between a Regular Bill and House Bill?

What is the difference between a Regular Bill and House Bill?

Regular Bill: defined as a non-Master bill of lading with NO UNDERLYING house bills.  For ISF, this is the bill reported to CBP in AMS, which is also referred to as “Straight Bill” or “Simple Bill”. 

House Bill: defined as a bill of lading issued under a Master Bill.  For ISF, this is the House Bill reported to CBP in AMS.  If multiple House Bills exist, the SF15 record is repeated accordingly.