For individual stock in history, you can check on sec.report such as https://sec.report/Ticker/YHOO
Thank you. If someone has the list of all tickers from 2006 including the delisted stocks, please kindly let me know and I am willing to pay for the list.
https://stockanalysis.com/actions/delisted/
has symbols of U.S. stocks delisted since 1998.
http://eoddata.com/symbols.aspx
has current symbols.
Of what use is knowing delisted companies stock symbols?
In indexes?Including delisted stocks in backtesting is necessary to avoid certain bias.