ISIN allocation guidance: changes to security alone do not trigger a new ISIN when core issuance terms remain unchanged. Clarification states that changes to the underlying security, creation of additional security, or creation of security for unsecured debt do not require a new ISIN provided core issuance terms (maturity, coupon, face value, redemption schedule or nature of the instrument) remain unchanged; Depositories shall not assign a new ISIN in such cases, and debenture trustees must ensure regulatory compliance when the underlying security changes.