QuoteOriginally posted by: meteorjust out of curiosity: what is the average size of prop trader book. Or more generally what is the AUM at a prop desk.I am asking that as I am wondering if there is a real big difference between trading in a prop desk or in a hedge fund (at the end of they they are both buy side).unlike hedge funds who manage external assets and therefore manage AUM, prop desks have capital allocated to them usually in the form of limits. so usually they manage their books against var (or other risk limits), but could also be position, concentration etc. therefore HFs are looking to generate a [positive] return on assets, while a prop desk cares about generating profits above funding and risk capital costs.since as a HF you usually have more capital then you need for the strategy (ie you rarely run at the limits of leverage) while at a prop desk you need to manage as capital efficent as possible (as capital costs) position sizing and trade implementation is quite different. i\ve seen a lot of prop traders struggle with this when trying to transition into managing client assets.