A system conducts anonymous negotiations and supports indications-of-interest (IOIs) in trading stock. The system includes a database for storing public orders received from a public stock trading system; and a server for receiving hidden orders from a plurality of users and for conducting anonymous negotiations between first and second users with the hidden orders. The server repeatedly accesses the database to determine a match of any one of the hidden orders with any one of the public orders, and to execute a pair of orders selected from the hidden orders and the public orders.