Donor's compensation as boss takes charge (4,3)

I believe the answer is:

stud fee

'donor's compensation' is the definition.

'boss takes charge' is the wordplay.
'boss' becomes 'stud' ('stud' can be a synonym of 'boss').
'takes' says to put letters next to each other.
'charge' becomes 'fee' (fee is a kind of charge**).
'stud'+'fee'='STUD FEE'

'as' is the link.

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app