A bill of lading represents receipt of goods by the carrier, and contracts between the owner of the goods and the carrier, to deliver those goods. There are primarily two types of ladings. A straight bill of lading is non-negotiable. A negotiable or shipper’s order bill of lading can be bought, sold, or traded while goods are in transit and is commonly used in letter of credit transactions. The owner of the cargo usually needs the original or a copy as proof of ownership to take possession of the goods.