Brief argument in place where shares are traded? (8)
I believe the answer is:
exchange
I believe this clue is a double definition.
'brief argument' is the first definition.
(I've seen this before)
'place where shares are traded?' is the second definition.
(stock exchange)
'in' is the link.
(Other definitions for exchange that I've seen before include "Fight -- angel chews box (anag)" , "Altercation" , "Swap, barter" , "Convert" , "Substitute" .)