Volunteer city investment (7,7)
I believe the answer is:
venture capital
'volunteer city investment' is the definition.
'venture capital' can be an answer for 'investment' (I've seen this before). I am not certain of the 'volunteer city' bit.
'city investment' is the wordplay.
'city' becomes 'venture' (I can't explain this - if you can you should believe this answer much more).
'investment' becomes 'capital' (I've seen this before).
'venture'+'capital'='VENTURE CAPITAL'
Can you help me to learn more?
(Other definitions for venture capital that I've seen before include "money invested" , "Risky investment" , "Money riskily put in" , "source of high-risk investment" .)