About to be sold as a concern may be (5)
I believe the answer is:
going
'sold as a concern may be' is the definition.
I can't judge whether this defines the answer.
'about to be' is the wordplay.
'about' becomes 'ing' (I can't justify this - if you can you should believe this answer much more).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'be' becomes 'go' (going is a kind of being).
'ing' put after 'go' is 'GOING'.
Can you help me to learn more?
(Other definitions for going that I've seen before include "repeated as sale nears completion" , "in action" , "It affects runners" , "fading" , "Progress" .)