Trading actual shares of a security in a round-lot-based system

A system for trading actual shares of a security, comprises:

• a computer system executing computer program instructions stored on a computer readable medium to:
• receive by a computer system configured to display quantities of orders for securities in round-lots actual share amounts of orders for trading of securities, at least one of the orders including an odd lot portion;
• and
• aggregate by the computer system the actual share amounts of the orders into an aggregate actual share amount;
• round down the aggregate of actual share amount to a nearest integer number of round lots;
• store the aggregate of actual share amounts on an order book that is stored on a computer readable medium that maintains orders for the securities;
• and
• disseminate to market participants the entered actual share amounts as the number of rounded down round lots.

A computer program product residing on a computer readable medium for trading actual shares of a security, comprises instructions for causing a computer to:

• receive actual share amounts of orders for trading of securities, by a program configured to display quantities of orders for securities in round lots at least one of the orders including an odd lot portion
• aggregate by the computer system the actual share amounts of the orders into an aggregate actual share amount;
• round down the aggregate of actual share amount to a nearest integer number of round lots;
• store the aggregate of actual share amounts on an order book that is stored on a computer readable medium that maintains orders for the securities;
• and
• disseminate to market participants the entered actual share amounts as the number of rounded down round lots.