What I was alluding to was if you and I both held 100,000 BTC for example, and we wanted to push up the value of BTC so facilitate a sell off in the future... b

What I was alluding to was if you and I both held 100,000 BTC for example, and we wanted to push up the value of BTC so facilitate a sell off in the future... because of our large holding it shouldn't be too hard for us to accept a loss while we buy/sell large quantities as long as we push the price up higher. If we were colluding to push the price up, we could both coordinate large buy/sell orders and dump them into the market adding volume and shifting the price a bit... people watching just see trades and see the price moving, thinking its credible trades... I could be wrong, but if market buy orders take the lowest offered, and market sell orders take the highest offered I think it would work as I imagine. This means those two parties now have a bunch of cash on hand and still hold a lot of BTC, they could now set a bot to continually put buy orders in at an escalating exchange rate. Also sell at an escalating exchange rate. Every now and then execute a large trade to push some volume into the market... it wouldn't work for every trade as normal people would jump in and buy or sell and take their cash/BTC... but on a long enough scale I think it would work.