> Exchanges that aren't stupid keep the vast majority of their funds in cold storage That sounds dumb on their part, as that money isn't doing work that it cou

> Exchanges that aren't stupid keep the vast majority of their funds in cold storage That sounds dumb on their part, as that money isn't doing work that it could. Perhaps they should invest it in the meanwhile. But since it's users' money, maybe set up a provision that only a part of the funds is invested, and the rest stay put, to give them back to the users on demand. Most people don't regularly take out all their coins at once, so the exchange won't need to have them all on hand, most of the time.