Scowling, having lost capital - it's bringing them down (8)

I believe the answer is:

lowering

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'scowling' is the definition.
(thesaurus)

I don't understand how the rest of the clue works.

(Other definitions for lowering that I've seen before include "Making less high" , "Reduction - long wire (anag)" .)

I've seen this clue in The Irish Times.

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