Advance by oneself reportedly (4)
I believe the answer is:
loan
'advance' is the definition.
(an advance is a loan)
'by oneself reportedly' is the wordplay.
'by oneself' becomes 'lone' (I've seen this in another clue).
'reportedly' shows a homophone (sound like).
'lone' sounds like 'LOAN'.
(Other definitions for loan that I've seen before include "Cash advance" , "Mortgage" , "temporary payment" , "Advance (money)" , "It's given but has to be returned" .)