Money invested in chief city (7)
I believe the answer is:
capital
I believe this clue is a double definition.
'money invested' is the first definition.
(capital invested in an enterprise)
'chief city' is the second definition.
(I've seen this before)
'in' acts as a link.
(Other definitions for capital that I've seen before include "Chief; excellent" , "Madrid, say" , "Most important city" , "Means" , "Principal city" .)