I just started using market on open orders and I'd like to know if they are always filled at the open price. Let's say in the first 5 minutes the stock goes down 1%. Would the market on open order get filled at the open or is there a risk that it would get filled at less? And how much less? I'm also considering limit on open but the problem is I'm not sure what to put for the limit price. I don't really care what I pay as long as it's the market open price. I hope that makes sense.