Reduced the commission (3)
I believe the answer is:
cut
I believe this clue is a double definition.
'reduced' is the first definition.
('cut' can be similar in meaning to 'reduced')
'the commission' is the second definition.
(thesaurus)
(Other definitions for cut that I've seen before include "Slice, chop" , "Saw" , "Slash" , "drunk" , "Abbreviate" .)