Patent ID: 8635144

Claim:
A method for facilitating trading of securities over a computer system, comprising the steps of: electronically receiving a first order for a security from a first user, along with a price for said first order; calculating with a processing system comprising one or more processors a block price range for said security, said block price range having an upper end and a lower end; determining with said processing system that said first order is reasonably priced, wherein the determining is based on whether said price satisfies the following conditions: for a sell order, said price is equal to or lower than said upper end of said block price range, and for a buy order, said price is equal to or higher than said lower end of said block price range; transmitting to a second user an electronic notification that a reasonably priced order for said security is present, but without notifying said second user of a side of the order; receiving a second order from said second user, along with a price for said second order, wherein said second order is contra to said first order, such that if said first order is a buy order, said second order is a sell order, and if said first order is a sell order, said second order is a buy order, and wherein said second order is reasonably priced but does not cross said first order; transmitting an electronic contra order notification to said second user after said second order is received, said electronic contra order notification indicating that a reasonably priced contra order is active within the computer system; receiving a third order, along with a price for said third order, from said second user, said third order being contra to said first order, such that if said first order is a buy order, said third order is a sell order, and if said first order is a sell order, said third order is a buy order, and wherein said third order crosses said first order; and executing a trade comprising said first order and said third order, wherein said second user receives said electronic contra order notification only after a second predetermined time period has lapsed after said second order is received, and wherein said step of calculating the block price range comprises predicting a price range likely to occur within a first predetermined time period.