Immoral investor's evil spirit (6,5)

I believe the answer is:

fallen angel

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'evil spirit' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'immoral investor's' is the wordplay.
'immoral' becomes 'fallen' (I've seen this before).
'investor' becomes 'angel' (term for a financial backer of new businesses).
'fallen'+'angel'='FALLEN ANGEL'

Can you help me to learn more?

(Other definitions for fallen angel that I've seen before include "Rebel spirit from heaven" , "Devil" , "outcast" , "Rebel against God" , "Former resident of heaven?" .)

I've seen this clue in The Times.

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