Patent ID: 8165947

Claim:
A method comprising: receiving, by at least one computer of an initial trading center for trading securities, an order to buy or sell a security, wherein the order includes information indicating (i) a symbol of the security, (ii) a side of the order, (iii) an order size indicating the number of shares of the security to buy/sell and (iv) a trigger quantity, wherein the trigger quantity is not a minimum fill quantity constraint, and wherein the order remains unexecutable until the trigger quantity is satisfied; and determining, by the at least one computer of the initial trading center, whether the trigger quantity is satisfied based on an available number of shares for the security, wherein the available number of shares is based on the aggregate of (i) the displayed and undisplayed/reserve liquidity for the Security at the initial trading center, and (ii) the displayed accessible liquidity at one or more away trading centers that is known to the initial trading center.