Annual return initially brings up unpaid debts (7)
I believe the answer is:
arrears
'unpaid debts' is the definition.
(I've seen this before)
'annual return initially brings up' is the wordplay.
'initially' says to take the initial letters.
'brings up' becomes 'rears' (rearing is a kind of bringing up**).
The initial letters of 'annual return' is 'ar'.
'ar'+'rears'='ARREARS'
(Other definitions for arrears that I've seen before include "Ourtstanding payments" , "State of being behind with payments" , "Amount unpaid" , "Back payments due on a debt" , "Unpaid debts" .)