He doesn't have to sell BTC back at a net loss. He uses his buying power to engineer those very positive BUY indicators that you mention. For example. Place a 2K Bitcoin wall right at a major resistance point. If there are a few panic sells at the Ask Wall, buffer the Bid wall up enough to absorb the selling pressure from all the little fishies looking to lock in profits. That way, the less twitchy little fishies will see that Bitcoin isn't going to fall and will hold. When market settles, Whales then move buffer pressure in Bid wall increasingly further up towards spot, so as to form an ascending triangle against the resistance price. AT some point, the whale might take away his 2K Ask wall and see if the little fishies start panic buying way up past the resistance point. Or he might simply buy up his own wall, resulting in a huge volume spike which will then ensure that the little fishies start panic buying, thus driving the prices up. The whales doesn't take a net loss. The whale uses his buying power to engineer the market into bidding the price up which in turn increases his net value. As I have said, I suppose the desired end game might be another stampede of fresh capital piling into Bitcoin. Then the whales can really cash in before they let the market fall, by selling their coin into the stampede of new capital and ceasing to support Bitcoin with their buying power.

Exchange fees from the continual swishing of BTC and fiat between accounts?

I am sure the very biggest players are on very good terms with the exchanges, and we now know that Karpeles had fee free accounts on MtGox through which 'Willy' and 'Markus' would ramp the price. But this is the market. It may be hooky but the fact is that their are certain forces at work just now intent on ramping Bitcoin up. Only they will know when the saturation point has come or when it is no longer prudent to ramp.

It is a highly engineered market. PHACT!