I found that for example ISIN have following rules:
Merger and acquisition: Old ISINs for stock become inactive and are replaced by securities with a new ISIN. Bonds only need new ISINs if old ones are exchanged for new ones.
So ISIN could be changed for a company.
I suppose the same rules are for CUSIP/SEDOL (an i right?)
Is there any way to link the new ISIN (CUSIP/SEDOL) with the old one? I mean when some companies were merged, and i have a ISIN of the new company - how can i see which companies the new company consists of (get ISINS(CUSIP/SEDOL) of initial companies)?
The same is for all ISIN (CUSIP/SEDOL) histories? Is it possible to get all ISINs for a company (for all periods)?