Instead of existing your stock positions with Market On Open, would it be preferrable to to have a limit order that's say 2% lower than yesterday's close (long position)? Would that limit order take part in the opening auction? TD Ameritrade has no dedicated MOO or LOO order type, while Interactive Brokers has time-in-force of OPG (opening). I would like my limit order to stay active throughout the whole day, from 9:28am (including opening auction) to 4:00pm. What are the odds of getting a worse fill with Limit order at 98% of yesterday's close vs plain Market on Open? Any idea how this would play out at foreign exchanges - Tokyo, Hong Kong, Frankfurt, Stockholm, when trading through IB? I also do limit my position to way under 1% of the daily dollar averaged volume. I understand that if the stock gaps down say 3% and keeps on going down I will be stuck in the position. I just want to limit maximum opening slippage to 2%.