Today, I submitted my first Hiden order with IB. It was 176 shares on IMGC, a LMT order "good till date", the exchange was "Island" and I checked Hidden (the only way to have an Hidden order with IB, as I understand). This order was filled less than 2 minutes after it was submitted. The cost was 2.29$ for this 176 shares.... The cost for 176 shares with a Smart routing is only 1$ ( Max(176*0.005$ ,1$) ). I asked IB using the chat, but i didn't receive a "good" explanation about the difference between 1$ and the 2.29$. So, if someone can help me to understand why it was 2.29$ instead of 1$, in detail, it'll be great.