Presumably contains a quantity of money (3)

I believe the answer is:

sum

'a quantity of money' is the definition.
(I've seen this before)

'presumably contains' is the wordplay.
'contains' indicates the answer is hidden within the clue.
'SUM' is hidden within 'presumably'.

(Other definitions for sum that I've seen before include "Mathematical problem" , "Quantity obtained by addition" , "All one has" , "Amount of money; total" , "See 25" .)

I've seen this clue in The Times.

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