the debate normaly is around what percent of the purchase price one should be prepared to lose, and in general a wider stop loss would be applied to a more volatile stock....
the other consideration is over what the period of time one is trading - ie longer periods of time wider margins ...
the third option is one that I had not previously considered and it assumes firstly that one is trading "with the trend".....
then the the stop/loss should be set at a level where it is considered that if the stock moves up or down to that level a change in trend is more likely..
then it follows on from that, in say an upward trending stock, since the stop level is constant, that there would be a lesser stop loss if the stock was purchased towards the bottom of the trading band than if purchased at a higher level within the trading band...
