Gem robbery liquidates stocks! (5)
I believe the answer is:
beryl
'gem' is the definition.
(beryl is a kind of gem)
'robbery liquidates stocks' is the wordplay.
'stocks' indicates a hidden word.
'BERYL' can be found hidden inside 'robbery liquidates'.
(Other definitions for beryl that I've seen before include "Emerald or aquamarine" , "Gemstone of which emerald is a variety" , "Blue, green or yellow mineral, sometimes a gemstone" , "- - Bainbridge (lit.)" , "Girl's name - jewel" .)