Manage an investment (4)
I believe the answer is:
cope
I believe this is a double definition.
'manage' is the first definition.
(manage can mean to cope or do well)
'an investment' is the second definition.
(I've seen this before)
(Other definitions for cope that I've seen before include "Manage, subsist" , "Deal with, manage successfully" , "Firmly based (in)" , "Survive" , "Join" .)