You will receive the market price at time of execution. M1 and all broker dealers have a duty of best execution. The duty of best execution legally requires brokers to seek the best execution reasonably available for all customer orders. To comply with this requirement, brokers evaluate the orders they receive from all customers in the aggregate and periodically assess which competing markets, market makers, or electronic communications networks (ECNs) offer the most favorable terms of execution. Some of the factors a broker must consider when seeking best execution of customers' orders include: the opportunity to get a better price than what is currently quoted, the speed of execution, and the likelihood that the trade will be executed.