very simple reason: take this for instance, some1 has 50 santas lets say there 5mil each, so he has 250mil of santas, now lets say he alchs 2 to 3 of em, looses 15mil, now if he displays or the ruenscape community finds out lets say their is a scare price goes to 6mil on stantas, now he has 47 at 6mil each, that makes i=his santas worth 282mil, a 32mil profit