Fortune Trump keeps after taxes (3)
I believe the answer is:
net
'after taxes' is the definition.
(I've seen this in another clue)
'fortune trump keeps' is the wordplay.
'keeps' says the answer is hidden in the clue.
'NET' can be found hidden inside 'fortune trump'.
(Other definitions for net that I've seen before include "Catch -- after all deductions" , "Tennis equipment" , "device to divide the court" , "Mesh; entrap" , "Mesh; profit" .)