A sporting investment aid (4)

I believe the answer is:

abet

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'aid' is the definition.
(I've seen this in another clue)

'a sporting investment' is the wordplay.
'sporting investment' becomes 'bet' (bet is a kind of investment. I am not sure about the 'sporting' bit.).
'a'+'bet'='ABET'

Can you help me to learn more?

(Other definitions for abet that I've seen before include "Encourage or assist (someone) to commit crime" , "helpful" , "Help a criminal" , "Help to do something wrong" , "Assist (in wrongdoing)" .)

I've seen this clue in The Globe and Mail.

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