Deposit after banks close and make a killing (4)
I believe the answer is:
slay
'make a killing' is the definition.
(I've seen this in another clue)
'deposit after banks close' is the wordplay.
'deposit' becomes 'lay' (I've seen this before).
'after' says to put letters next to each other.
'banks close' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'lay' put after 's' is 'SLAY'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for slay that I've seen before include "Violently kill" , "Kill (literary)" , "Destroy" , "Butcher" , "Fatally hit" .)