Engels naar Nederlands Juridisch / patenten Juridisch (algemeen)

Weet iemand misschien wat de juiste nederlandse vertaling is van een "first demand bank guarantee"? De context staat hieronder. Alvast bedankt!

Since this third building permit has not yet been granted by the public authorities, the Sellers granted one of my group companies, R. S. S.r.l., which subsequently amended its name to G. S.r.l., a first demand bank guarantee issued by the Banca Nazionale del Lavoro S.p.A. for the amount of Euro 500,000.00 (Five Hundred Thousand)