All these replies telling you this isn't possible are amazing. Perhaps they are forgetting that when you hold coins at Coinbase that's no different from a bank

All these replies telling you this isn't possible are amazing. Perhaps they are forgetting that when you hold coins at Coinbase that's no different from a bank giving you a bank note saying you "own" x amount of gold in their vault. EDIT: I was obviously not the first to say this but it is really interesting to watch the crypo space re-invent all of modern finance, one piece at a time.