For example : I want to buy SPY at 125.001 and not at 125.01 TWS don't allow me price like .001 or 0.0001 Why ??????
cause you asking too much. no sub penny for retail. this allow wall street cheaters step on front of your order. and they do that all the time. welcome to my world of pain.. tell you more- sub penny orders are not even displayed for us in T&S or L2 or market depth. everything is rounded to 2 digits after decimal point. to fool us,the retail traders
TWS allows you to price your order in multiples of minimal price increments, which are decided by the exchange and vary between various instruments. You cannot submit a SPY order priced at 125.001 to IB, because we would be not able to send it to an exchange with that price; the min incr for SPY is 0.01. The sub-penny increments are allowed for US stocks with price under $1.