I respect Mark Cuban as well. Although I think you misunderstood his comments a bit. By saying that bitcoin is in a bubble I don't think he suggested that someone should sell. What I mean by that is, think of the dot com bubble. Everyone was bying into technology at that time and making money until the bubble burst. Yes a lot of money was lost and many companies went bankrupt but not all of them. Look at the companies that made it through where they are right now. Bitcoin IS in a bubble like it or not. Nobody knows how high it will go before the bubble bursts. All I'm saying and probably what Mark Cuban was trying to say is, crypto currency definitely has a future. Make it yourself and don't buy you way into it because of the hype there is on the subject.