Greetings, I've been a member here for a bit and browse on occasion. I just wanted to give people a heads up. I'm not sure how many this will affect on the board but I hope it helps. Apologies if this is in the wrong forum. My firm uses IB's cost-plus (unbundled) commission structure for trading in our client accounts, as we regularly achieve a trading volume in the millions of shares a month and, when combined with getting liquidity rebates, can reduce effective rates well below 0.003/ share. Anyway, I recently noticed that for a particular ETF (QQQ), the commissions my clients were charged by were greater than what my trade platform calculates they should have been. After some digging and confirmation with IB chart, it turns out this was due to an error in IB's programming, and one which they quickly rectified. It turns out that for all NASDAQ / ISLAND MOC orders, the exchange fee is 0.001 / share (which is what I was using), but IB was charging the full 0.003 / share fee for removing liquidity. Like I said, IB quickly rectified the error and I am in the process of crediting my client accounts for the difference, but I wanted to make others aware of this so that if they were affected they can pursue compensation. While I may have certain frustrations with the way IB does things, I will say they were very quick to address this problem, admit fault, and fix it. So if you trade unbundled at IB and trade using MOC orders on ISLAND or NASDAQ, then please be aware of this issue. Also, it's good to sample your charged commissions vs correct commissions because you never know when the broker may be getting things wrong. I hope this helps.