Swaps (6)
'swaps' is the definition.
('trade' can be a synonym of 'swap')
This is all the clue.
(Other definitions for trades that I've seen before include "Swaps - winds" , "Barters" , "Exchanges, buys or sells" , "Buys and sells shares" , "Stared (anag)" .)
(Another definition for switches that I've seen is " changes".)