I recently found a stock certificate for 23 shares of Agency Rental Car dated 1993.
Avis purchased Agency Rental Car. What is the current value of the stock listed in the certificate (2012)

Avis has been through a lot of corporate restructuring over the years. Do you know what year Avis acquired Agency? If it was before 2001 then when Avis bought Agency the owner of the stock would have received Avis shares, then later when Cendant bought Avis those shares would have been exchanged for Cendant shares, and then when Cendant split into 4 companies in 2006 the Cendant shares would have been exchanged for shares in Wyndham, Realogy, Travelport, and Avis Budget Group. Clearly it's complicated - hence I suggest you contact either Avis Budget Group Investor relations: Avis Budget Group: Investor Contacts or the stock transfer agent for Avis Budget Group: BNY Mellon | Asset Management and Securities Servicing to see if that old certificate has any value.