ISIN is needed to set up master security files. Best is on date of offering. Minimum is prior to first settlement date. This frequently results in assignment delays and multiple assignment that inhibits the use of ISIN as the global standard in some cases. The bottom line is that all instruments need a number.
Clarification is needed on the rules of assignment.
Minimal SLA requires disclosure and publication of all local NNA rules of assignment and reconciliation of those rules to the ISO standard. In addition, the industry would like to see a real-time communication mechanism in place to notify the industry of fixes to this type of problem as well as a link created between the numbers. Minimal SLA requires ANNA to designate the official NNA in each country and if more than one, to designate which class of securities the NNA is authorized to assign ISINs for. An exchange and currency identifier is critical to investment managers and custodians for valuation reporting and corporate action processing. This maintenance dilemma results in exception conditions and manual processes.