Money to invest in a hole in California (7)
I believe the answer is:
capital
'money' is the definition.
(I've seen this before)
'a hole in california' is the wordplay.
'hole' becomes 'pit' (pit is a kind of hole).
'in' is an insertion indicator.
'california' becomes 'cal' (short for California).
'a'+'pit'='apit'
'apit' placed inside 'cal' is 'CAPITAL'.
'to invest in' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for capital that I've seen before include "Cardinal; splendid; assets" , "liquid assets" , "Chief; excellent" , "Money saved or invested - seat of government" , "Upper case city" .)