Letter of credit guarantee. Letter of credit is a common payment method in international trade, and banks, as a third party, provide guarantees for the transactions between buyers and sellers. The letter of credit itself is not a bank loan guarantee, but a trade financing tool, which is used to ensure the payment and delivery of buyers and sellers, rather than the repayment of bank loans. The common loan guarantee methods of Chinese banks are mortgage guarantee, pledge guarantee, guarantee guarantee and deposit guarantee.