Since World War II new security devices have evolved in both France and the United States. In France, the new device is known as the first demand guarantee. In the United States, it is called standby letter of credit. The underlying market forces which caused these devices to be developed are the same. But the label applied to the devices and the bodies of existing doctrine with respect to which they are formulated is different. In the French view, the difference between the two instruments is just a matter of different labels. But in the American view, the distinction between a credit and a guaranty is critical. The purpose of this thesis is to compare the first demand guarantee and the standby credit, identifying both the similarities and the differences in these devices.