By order of your business, NBG issues Letters of Credit to ensure the fulfillment of your contractual obligations, whether financial or of other type.   
Depending on the nature of the risk being undertaken, the Letters of Credit are classified in two broad categories:  
a) those of formal content, where the Letters of Credit of category A are classified (such as participation in tenders). 
b) those of material content, where the Letters of Credit of category B (such as good performance of contractual terms) and of category C (such as payment of various obligations) are classified.