Company deficit by American giant (8)
I believe the answer is:
colossus
'giant' is the definition.
('colossus' can be a synonym of 'giant')
'company deficit by american' is the wordplay.
'company' becomes 'co' (abbreviation).
'deficit' becomes 'loss' (I've seen this before).
'by' means one lot of letters go next to another.
'american' becomes 'us'.
'co'+'loss'+'us'='COLOSSUS'
(Other definitions for colossus that I've seen before include "VIP" , "Abnormally powerful person" , "The - - of 19" , "Gigantic figure" , "An immense statue, once a wonder in Rhodes" .)