| Noun | 1. | unlisted security - a security traded in the over-the-counter marketcertificate, security - a formal declaration that documents a fact of relevance to finance and investment; the holder has a right to receive interest or dividends; "he held several valuable securities" OTC stock, over the counter stock, unlisted stock - stock that is not listed and traded on an organized exchange listed security - a security that has been accepted for trading by one of the organized and registered securities exchanges in the US |