First answer would obviously be "maximise risk-adjusted return". But if you break it down into the key components, what does his job actually consist of? For example, a boxer's job is to beat his opponent. Breaking it down into the key components, his job is to hit the opponent repeatedly, whilst avoiding being hit himself, aiming to KO his opponent or, if not possible, to defeat him on points by being more effective during the bout. A mechanic's job is to repair and service vehicles. Breaking it down into components, his job consists of surveying the vehicle, finding out what is wrong, selecting the appropriate repair technique and parts needed, then carrying out the repair. So, what's a trader's job, if you break it down into the component parts?