Employing American over Dutch bank (5)
I believe the answer is:
using
'employing' is the definition.
(to employ is to use)
'american over dutch bank' is the wordplay.
'american' becomes 'US' (United States).
'over' says to put letters next to each other (in a down clue, some letters go over others).
'dutch bank' becomes 'ING' (ING Group, Dutch banking corporation).
'us'+'ing'='USING'
(Other definitions for using that I've seen before include "Exploiting for one's own advantage" , "practice" , "having recourse to" , "Employing" , "Putting to a particular purpose" .)