A method, executed in a computer system, for opening an electronic market for trading of a security is described. The method includes receiving by the computer system eligible orders and quotes for the security traded in the electronic market and disseminating an order imbalance indicator indicative of predicted trading characteristics of the security at the open of trading. The method also includes determining by the computer system a price or prices at which the maximum shares would be executed and determining which price would minimize any imbalance of eligible orders and executing at least some of the eligible orders at the determined opening price.