Outlaw back to work for financial institution (4)
I believe the answer is:
bank
'financial institution' is the definition.
(bank is a kind of financial institution)
'outlaw back to work' is the wordplay.
'outlaw' becomes 'ban' (banning is a kind of outlawing).
'back to' suggests the final letters.
The final letter of 'work' is 'k'.
'ban'+'k'='BANK'
'for' acts as a link.
(Other definitions for bank that I've seen before include "Edge (of river) - tier (of oars)" , "area by river" , "River's edge" , "Sloping land" , "Long mound; rely (on)" .)