Looks like they've made about 8k btc's in the last 30 days or somewhere around there. If they're holding them thats great, but it would be nice to be more open about it. If they sell they get to collect fees again from the unsuspecting buyer. Not saying this is the case but you never know these days.
You write in a tone as if this would be something "wrong". Any why would you want to know what do they do with their money, be it BTC, or USD, or do they exchange one to the other. Does MtGox ask you how do you spend your money?
They can exchange their USD or BTC one way or the other on their own exchange like any other customer, and its nobody's else business. I bet they trade them back and forth whenever its convenient for them or they see opportunity for profit, be it for falling/rising exchange rate, or just for the extra 0.65%. The more they trade it, the better for the market because it gets more liquidity.
Anyone whining about them making an extra 0.65% out of the 0.65% fees they already made, should just mind his own business, instead of picking at perfectly legitimate trading.
