Retrieving historical ISIN → current ISIN mappings through the Python API

Question

Hi everyone,

I'm trying to understand how identifier changes are handled in LSEG data and whether the relationship between historical and current ISINs can be accessed programmatically through the Python API.

For example, when searching for the old ISIN NO0010299068 in Data Item Browser, the returned data corresponds to the current ISIN NO0013186460. This suggests that, in the backend, the old ISIN is linked to the current security record.

This is just one example. My actual use case involves many securities that may have undergone ISIN changes over time.

My question is:

* Is there a way, via the Python API, to start from an old/obsolete ISIN and retrieve the corresponding current ISIN?

Jirapongse Phuriphanvichai · Answer

An ISIN can be mapped to several RICs in different exchanges. I am not sure if this code can return a primary RIC.

response = search.lookup.Definition(
    view=search.Views.SEARCH_ALL,                              
    scope="OldQuoteISINs",                                                      
    terms="NO0010299068,PA1436583006,US5128071082",              
    select="BusinessEntity,DocumentTitle,IssueISIN,RIC").get_data()

response.data.df

Then, a RIC can be used to retrieve SymbolHistoryScope.

df = ld.discovery.search(
    view = ld.discovery.Views.EQUITY_QUOTES,
    filter = "RIC eq 'ENSU.OL'",
    select ="SymbolHistoryScope")
df["SymbolHistoryScope"][0]

Saad El-Haimar-El-Boukhari · Answer

Thanks a lot for your response, that’s very helpful.

One follow-up question:

Is there a way to retrieve the historically valid primary exchange RIC for an ISIN as of a given date? My goal is to account for cases where the primary exchange, and consequently the primary RIC, may have changed over time.

Jirapongse Phuriphanvichai · Answer

You can also use the following code.

import lseg.data as ld
from lseg.data.content import search

ld.open_session()

response = search.lookup.Definition(
    view=search.Views.SEARCH_ALL,                              
    scope="OldQuoteISINs",                                                      
    terms="NO0010299068,PA1436583006,US5128071082",              
    select="BusinessEntity,DocumentTitle,IssueISIN").get_data()

response.data.df

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