Abstract: The disclosed invention is a new method and mechanism for a marketplace of buyers and sellers of any asset, and in particular financial instruments. The invention includes a user specified, computer-aided control over the visibility and matching of buy and sell orders. In a marketplace, particularly one with illiquid assets, a participant wants his order to be shown to potentially interested participants such that a trade can take place. However, the participant wants this order treated with discretion, so that his trading information does not get into the hands of non-interested parties who may take advantage of the information, thus causing adverse price movement. The mechanism and business method disclosed herein allow the user to enter a buy or sell order along with parameters, including a visibility group, which guide a computer program to distribute information about this order to desired parties.