Trade bills, resulting from a sell and buy transaction, written by the buyer to the order of the seller who deducts them at the bank under his own guarantee. In this case, the one making the deduction (trader of seller) is a customer of the bank. The bank sets a ceiling for the customer to discount the endorsed trade bills resulting from true trade transactions. The ceiling is renewed yearly. Interest and commissions are paid in advance at each discount, and are settled in installments per agreement between the customer and the bank and according to due dates of the discounted bills.