From Wiktionary, the free dictionary
From un- + tradable.
untradable (not comparable)
- Impossible to trade.
2007 November 7, David Barboza, “Little-Known Entrepreneurs Putting China Near Top of Billionaires List”, in New York Times[1]:Analysts are skeptical about the way China's stocks are valued, particularly those like PetroChina with huge amounts of untradable government shares.