Not enough corresponding insurance business? (12)

I believe the answer is:

underwriting

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'insurance business?' is the definition.
The answer and definition are not the same part of speech.

'not enough corresponding' is the wordplay.
'not enough' becomes 'under' (I am not sure about this - if you are sure you should believe this answer much more).
'corresponding' becomes 'writing' (writing is a kind of corresponding).
'under'+'writing'='UNDERWRITING'

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I've seen this clue in The Irish Independent.

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