CUSIPs are identifiers created and delivered by the CSB (CUSIP Service Bureau). The CSB is managed on behalf of the American Bankers Association by Standard & Poor’s. Issuer codes are assigned alphabetically from a series that includes deliberate built-in ‘gaps’ for future expansion. The first six characters which are known as the base (or CUSIP-6) uniquely identify the issuer. Refer to https://www.federalreserve.gov/apps/reportingforms/Report/Index/FR_Y-14Q for more information.