Wikipedia
NSIN
A National Securities Identifying Number or NSIN is a generic nine-digit alpha numeric code which identifies a fungible security. The NSIN is issued by a national numbering agency (NNA) designated for that country. Regional substitute NNAs have been allocated the task of functioning as NNAs in those countries where NNAs have not yet been established. NSINs are used as part of the makeup of a product's ISIN.