Book in P.O. Box for corporation (3-5)

I believe the answer is:

pot-belly

'corporation' is the definition.
(corporation can humorously mean belly fat)

'book in p o box' is the wordplay.
'book' becomes 'b' (abbreviation for book).
'in' is an insertion indicator.
'box' becomes 'telly' (both can mean a television set).
'p'+'o'+'telly'='potelly'
'b' put inside 'potelly' is 'POT-BELLY'.

'for' is the link.

(Another definition for pot-belly that I've seen is " Protruding stomach".)

I've seen this clue in The Independent.

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