Bank amounts (8)
I believe the answer is:
'bank amounts' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for balances that I've seen before include "Keeps in equilibrium, like credits and debits" , "Scientific instruments" , "Equalises, offsets" , "Tallies" , "Is poised; sums in account" .)