I already mentioned below that I thought your site was nicely done. But you didn't answer my questions directly which makes me a bit wary.<p>My questions aren't site security questions per se, they deal more with the business of your site. Also, my questions are blunt, but not disrespectful, so don't be offended.<p>1) How do I trust <i>you</i>? How do I know you're not going to run away with all my money? Who are you?<p>Registered brokerage accounts have segregated funds, so that brokerages can't get access to my money in case the brokerage goes under. You are saying everything is in one giant account. In the case you suffer a catastrophic loss, how do I know my money is safe? Also, how do I know you're not Madoff and won't run away with all the money?<p>2) How are you affording the ability to margin people's accounts? Where are you getting the money?<p>3) You say you check for margin requirements every 5 seconds? If I were a market manipulator, I would wait for the order book on BTC to thin out, then I would massively short the markets. This would hopefully trigger massive margin calls on your end, and forced liquidation. Since the order book is thin, I would probably be able to cover at rock bottom prices. Also, presumably you (the site) would suffer tremendous losses.<p>How do you protect your customers from this?