Distributed matching system

Claim 1

A matching system for trading instruments in which bids are automatically matched against offers for given trading instruments for automatically providing matching transactions in order to complete trades for said given trading instruments, said system comprising a host computer means for maintaining a host book database comprising all of the active bids and offers in the system by trading instrument; a transaction originating keystation means for providing a bid on a given trading instrument to said system for providing a potential matching transaction; and network means for interconnecting said host computer means, said transaction originating keystation means and said counterparty keystation means in said system for enabling data communications there between, both said transaction originating keystation meand and said counterparty keystation means for said potential matching transaction each having an associated local database keystation book having an associated data storage structure and comprising a subset of said host book, said host computer means dynamically determining said local data base data storage structure, the content of each of said keystation books having an associated display depth range dynamically controllable by said host computer means and being dynamically updatable by transaction update broadcast messages received from said host computer means through said network means, said transaction originating keystation means and said counterparty keystation means comprising means responsive to said received transaction dynamic update broadcast messages for updating said associated keystation books and further comprising means for providing directed messages to said host computer means corresponding to said bid and said offer, respectively, said directed messages updating said host book, said host computer means comprising means for conditionally providing said transaction broadcast update messages to said keystation means in response to the presence of an update condition, said update condition comprising updating of said host book and said received bid or offer having a relative value compared with other bids or offers within said host book which is within said keystation book dynamically controllable display depth range of relative values; whereby controllable subsets of a distributable system trading book may be selectively provided to trading keystations in said matching system from the host for dynamically controllably masking the available trading market.