History of extinct or delisted symbols

[rahzan]

I apologize in advance if this is the wrong place for questions
For historical testing over many years often there are symbols that were changed, delisted or taken private.

Does Alphavantage provide history on such symbols. (I've tried and failed but I can't be sure if it is because I have a free API-key)

If yes, the problem is compounded by exchanges recycling symbols, is it possible to look up stocks by their name or CUSIP?

I have not been able to get any answers after two emails in two weeks fro the support email.
I doubt I'd want to pay $25/mo and receive no technical support.

[xrgarcia]

All good, happy to help in any way! To the best i can tell alpha vantage does not offer direct queries by CUSIP. You can search for a company by name.
View the api docs here.
A sample search:

https://www.alphavantage.co/query?function=SYMBOL_SEARCH&keywords=BA&apikey=demo

produces the following results:

{
    "bestMatches": [
        {
            "1. symbol": "BA",
            "2. name": "Boeing Company",
            "3. type": "Equity",
            "4. region": "United States",
            "5. marketOpen": "09:30",
            "6. marketClose": "16:00",
            "7. timezone": "UTC-04",
            "8. currency": "USD",
            "9. matchScore": "1.0000"
        },
        {
            "1. symbol": "BAB",
            "2. name": "Invesco Taxable Municipal Bond ETF",
            "3. type": "ETF",
            "4. region": "United States",
            "5. marketOpen": "09:30",
            "6. marketClose": "16:00",
            "7. timezone": "UTC-04",
            "8. currency": "USD",
            "9. matchScore": "0.8000"
        },
        {
            "1. symbol": "BA.LON",
            "2. name": "BAE Systems plc",
            "3. type": "Equity",
            "4. region": "United Kingdom",
            "5. marketOpen": "08:00",
            "6. marketClose": "16:30",
            "7. timezone": "UTC+01",
            "8. currency": "GBX",
            "9. matchScore": "0.6667"
        },
        {
            "1. symbol": "BABA",
            "2. name": "Alibaba Group Holding Ltd",
            "3. type": "Equity",
            "4. region": "United States",
            "5. marketOpen": "09:30",
            "6. marketClose": "16:00",
            "7. timezone": "UTC-04",
            "8. currency": "USD",
            "9. matchScore": "0.6667"
        },
        {
            "1. symbol": "BA3.FRK",
            "2. name": "Brooks Automation Inc",
            "3. type": "Equity",
            "4. region": "Frankfurt",
            "5. marketOpen": "08:00",
            "6. marketClose": "20:00",
            "7. timezone": "UTC+02",
            "8. currency": "EUR",
            "9. matchScore": "0.5714"
        },
        {
            "1. symbol": "BAAPX",
            "2. name": "BlackRock Aggressive GwthPrprdPtfInvstrA",
            "3. type": "Mutual Fund",
            "4. region": "United States",
            "5. marketOpen": "09:30",
            "6. marketClose": "16:00",
            "7. timezone": "UTC-04",
            "8. currency": "USD",
            "9. matchScore": "0.5714"
        },
        {
            "1. symbol": "BAAAAX",
            "2. name": "Building America Strategy Port CDA USD Ser 21/1Q MNT CASH",
            "3. type": "Mutual Fund",
            "4. region": "United States",
            "5. marketOpen": "09:30",
            "6. marketClose": "16:00",
            "7. timezone": "UTC-04",
            "8. currency": "USD",
            "9. matchScore": "0.5000"
        },
        {
            "1. symbol": "BAAAFX",
            "2. name": "Building America Strgy Portf CDA USD Ser 2022/2Q MNT CASH",
            "3. type": "Mutual Fund",
            "4. region": "United States",
            "5. marketOpen": "09:30",
            "6. marketClose": "16:00",
            "7. timezone": "UTC-04",
            "8. currency": "USD",
            "9. matchScore": "0.5000"
        },
        {
            "1. symbol": "BAB3.LON",
            "2. name": "Leverage Shares 3x Alibaba ETC",
            "3. type": "ETF",
            "4. region": "United Kingdom",
            "5. marketOpen": "08:00",
            "6. marketClose": "16:30",
            "7. timezone": "UTC+01",
            "8. currency": "USD",
            "9. matchScore": "0.5000"
        },
        {
            "1. symbol": "BAAX39.SAO",
            "2. name": "Ishares Msci All Country Asia Ex Japan ETF",
            "3. type": "ETF",
            "4. region": "Brazil/Sao Paolo",
            "5. marketOpen": "10:00",
            "6. marketClose": "17:30",
            "7. timezone": "UTC-03",
            "8. currency": "BRL",
            "9. matchScore": "0.3636"
        }
    ]
}

Give it a try and let me know how it goes. I'm very sorry you haven't found what you needed.

[rahzan]

Thank you very much.
I knew about the SYMBOL_SEARCH but I didn't realize it also searches the names as well for a sub-string. Alas, the more important need is getting data on delisted symbols, which based on the name-search, is NOT possible. Historical testing of portfolios invariably includes looking at defunct symbols. Therefore historical data is of only limited use if not all history is available; no different than missing a part of history on an active symbol.

I thank you again for your kind reply.