What whill happen if I enter a buy stop order with stop price lower than the current market price? Will this buy stop order simply be rejected by the exchange, or it is elected to market order and got executed immediately? Does different exchange have different rule to handle such scenario? For those exchanges where stop order is not a native order type, how do brokers simulate stop order in such a scenario? Do they do a sanity check to ensure the buy stop price is higher than the current market price? Help is appreciated.