The @hive.fund account does not release new hive to the market. It only dishes out HBD. We can make the case that it contributes indirectly to the selling pressure if those HBDs are converted to hive but the amount that is distributed via proposals is small compared to what is printed via rewards.
Sure, it's only 10% whereas the content rewards are 65%.
Currently the lack of markets for HBD make it practically imposible to reduce the selling pressure of hive. People need to convert or trade their hive dollars on the internal market instead of selling them directly on exchanges.
It's traded against BTC on Upbit and Bittrex.
The problem with the lack of exchanges for HBD is that not everybody can use the existing ones. Both require KYC and on Upbit you need to be a korean national or use the branch for Indonesia. Bittrex is a USA exchange that has very stringent requirements to use. So most users are unable to trade them directly for BTC. Either they use a third party like blocktrades which carries an additional cost in fees or they exchange for Hive and then sell that on another exchange.