Re short positions2 Jul 2015 11:46
" If the price starts to creep up, they can either sell a few shares they have already borrowed to depress the price down again or they can take out a further short position to sell a few more and manufacture a price drop. What is static about that????"
No, of course that's not static, but that's exactly what I was saying. They have to keep increasing their short position to overcome any net balance of buys over sells. If the short position were to remain static it would not act as a cap as tricky initially indicated.