As a bitcoiner, trader and investor, talk of a bitcoin ETF worries me. Bitcoin is obviously a major threat to the banking system. Once an ETF is in place it gives banks the ability to ‘naked short’ the product and sell something they don’t own. Commodity ETFs also trade volumes in excess of a years supply of the actual commodity in a single day because they are so detached from reality. We could soon see the banks selling MILLIONS of ‘ETF bitcoins’ that don’t actually exist in order to drive down the price . BUT…Commodity ETFs give the owner of the shares the ability to demand physical deliver but traders rarely do for obvious reasons. With bitcoin however it is fast and simple to take delivery from the ETF so it will be interesting to see if the Winklevoss twins 100% back the ETF with bitcoins and how detached from the real world of bitcoin the ETF would become.