What you said is not clear. I have three understandings: 1. If you apply to open a letter of credit of 5 million dollars, you have to pay 5 million dollars to the bank. If the bank has a credit line of $654.38+00,000, you only need to pay $4 million as a guarantee; If you want to open a letter of credit of $800,000, you also have a credit line of $6,543,800+0,000. According to bank regulations, you may not pay the letter of guarantee or the minimum amount (for example, 654.38+00% = $80,000). 2. If the beneficiary or the negotiating bank thinks that the credit of the issuing bank is insufficient, ask another mutually agreed bank with high credit to guarantee (payment, also called confirmed letter of credit). 3. There is also a standby letter of credit as a guarantee document, which can also be understood as a letter of credit guarantee. I wonder what kind of situation you belong to. You'd better make it clear later. You cherish words like gold, and I write a thousand words.
Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.