At first, good rates allow banks to provide interest (4)
I believe the answer is:
grab
'interest' is the definition.
(I know that fascinate is a is a kind of of grab)
'at first good rates allow banks' is the wordplay.
'at first' suggests taking the first letters.
The first letters of 'good rates allow banks' is 'GRAB'.
'to provide' acts as a link.
(Other definitions for grab that I've seen before include "Seize suddenly" , "Seize roughly" , "Take quickly" , "interest" , "Grasp roughly" .)