O-15 is a classification on the Pay Grade Scale for the Dragonian military.  Capped by executive fiat, a soldier with the pay grade of O-15 makes about 655 billion credits per month.

Unlike typical instances of being paid, the pay grades above O-10 have responsibilities tagged onto them.  An O-15 is responsible for organizing the amount of money required to run social programs, public works projects, general City-State expenses and maintain the overall military of the nation.  Whatever is left over from fulfilling the financial duties of the O-15 is to be distributed by the O-15 as they see fit.