ISIN CUSIP SEDOL ISMA number

ISIN CUSIP SEDOL ISMA number
http://en.wikipedia.org/wiki/International_Securities_Identifying_Number
都是表示issue level的security code。CUSIP主要用于北美证券市场而SEDOL主要用于英国和爱尔兰。9位的CUSIP前加上两位国家代码，最后一位加上check digit，就构成了12位的ISIN。7位的SEDOL前面加上两位国家代码和两个零空位，最后一位加上check digit，构成12位的ISIN。
对ISMA number不太清楚。好像是ISMA和IPMA合并成ICMA了。
Third party may have no RIC, they use VALOREN instead.
 
CUSIP:

1. Committee on Uniform Security Identification Procedures 9-character alphanumeric security identifiers that they distribute for all North American securities The CUSIP distribution system is owned by the American Bankers Association and is operated by Standard & Poor's.
2. The first six numbers identify the organization issuing the security. The next two characters identify the issue itself.

http://www.ejv.com/bp/html/glossary3.html

SEDOL:

1. Stock Exchange Daily Official List used in the United Kingdom and Ireland
2. seven characters in length, consisting of two parts: a six-place alphanumeric code and a trailing check digit.