Any IB users, Learn from my recent experience and don't trust what the TWS Portfolio page or the Trades window and report states your position is. I scale in and out and add to and lighten positions all day so I have always counted on my execution software to keep track of my current position for me. One day about 2 months ago now, I closed TWS with the Portfolio page and Trades report saying I was flat ES. The next morning when I started TWS I was long 1 ES contract. As luck would have it, ES was down close to 20 points overnight. I called IB to make sure the position was mine and hadn't been accidentally moved to my account by some system glitch before closing it and flattening out. IB verified that it was mine and told me I must have overlooked the position the previous day. After a month of sending log files and execution reports to IB, the customer service rep confirmed that there had been a bug in that version of TWS that caused some executions to not be reported, and this issue had been reported by other users. When I made a compensation request, however, I was rejected with the message that the review of my activity did not conclusively show an error with TWS; and that I should have checked my trade confirmations on the website. I was told that an experienced trader should always know his position. Of course I agree with this, but with any execution software I've ever used, I've been able to rely on the execution log to correctly display trades. And in 5+ years of using IB, I'd never had a trade not show up in the Portfolio page or Trades report. I've always been happy with IB and have recommended it numerous times, but I was very disappointed in them throughout the whole process of dealing with this issue. I've never had much dealing with customer support -- I've only ever contacted them a few times, but I now know why there are so many complaints here about their condescending and arrogant manner. One example: on my first call to verify that the position was real I was told "You wouldn't be calling if it had moved in your direction." Then several times while trying to track down the problem I was told the programmers would look into something. After a week or more without hearing from anybody, I would have to contact support again to find out the status. I've never asked for compensation from a broker before this issue, though I've had other brokers voluntarily compensate me after software problems. This, though, seemed like a very reasonable request to me. I know I'm a smalltime trader, but given that I did $55,000 in commission at IB last year, asking for $1000 in compensation for a loss directly caused by a confirmed software bug seems fair. After initially rejecting my request, IB did later make a partial compensation offer, though I didn't accept it out of (foolish) principle. I guess I should be happy that the position was only 1 contract. Overall, I still think IB is a good broker, but their customer service department suffers from an apparent culture of arrogance and "the customer is always wrong" attitude. It's unreasonable to expect any trading platform to always be completely bug-free, but I do expect issues to be handled in a much better manner than this one was.