I have all the CIKs and relative tickers of all the traded securities that I need (https://www.sec.gov/include/ticker.txt).
My question is: How do I find the stock exchange that a gives security is traded in, given any CIK? (I am looking for an official data source for this, possibly the sec.gov website)
I found some other unofficial sources which I could use, like those: (http://oatsreportable.finra.org/OATSReportableSecurities-SOD.txt) (https://rapidapi.com/logicione/api/stock-ticker-security-and-company-search-database) (https://sec.report/CIK)
But I don't know where do they get their data from, and it does not always correspond to the data I get from the SEC website, so I would like to find some "official" data, possibly from the sec.gov website.