Obtains inside information given rise in savings (4-3)
I believe the answer is:
nest egg
'savings' is the definition.
(nest egg can mean someone's savings)
'obtains inside information given rise' is the wordplay.
'obtains' becomes 'gets' ('get' can be a synonym of 'obtain').
'inside' indicates putting letters inside.
'information' becomes 'gen' (gen can informally mean information).
'given rise' says the letters should be written backwards (in a down clue, letters go up).
'gets' going into 'gen' is 'ggetsen'.
'ggetsen' written backwards gives 'NEST-EGG'.
'in' acts as a link.
(Other definitions for nest egg that I've seen before include "Sum saved for the future" , "Savings for the future" , "Retirement savings" , "Saved-up money" , "Money set aside for retirement" .)