Sell small company making musical instruments (6)
I believe the answer is:
cellos
'musical instruments' is the definition.
(cello is a kind of musical instrument)
'sell small company' is the wordplay.
I cannot really see how this works, but
'small' could be 's' (abbreviation - e.g. clothes size) and 's' is found within the answer.
The remaining letters 'cello' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'making' is the link.
Can you help me to learn more?
(Another definition for cellos that I've seen is " Large stringed instruments".)