Principal assets (7)
I believe the answer is:
capital
This clue is a double definition.
'principal' is the first definition.
(I've seen this before)
'assets' is the second definition.
(I have seen 'liquid assets' mean 'capital' so perhaps 'assets' could also mean 'capital')
(Other definitions for capital that I've seen before include "savings" , "It's terrific in the big city" , "Most important city" , "Cardiff, say" , "Major city - investment - great!" .)