When parties agree commercial terms in a contract, one of the terms will include the interval between the buyer receiving a correct invoice and the buyer making payment of the agreed sum. The actual terms agreed will reflect the balance of power between the parties and the degree of trust in the relationship. In some international transactions, the seller may insist upon a Letter of Credit, while if the buyer is in a powerful position they may insist that payment occur 30 or 45 days after receipt of the invoice.