1. A financial instrument transaction system, comprising: a database configured to store financial instrument information for certain reference entities; memory configured to store execution instructions; and a processor coupled with the database and the memory, the processor configured to execute the instructions, the instructions configured to cause the processor to: initiate a trading session for a predetermined duration; prior to and during the trading session, receive from each of a plurality of trader clients trading instructions associated with a reference entity, the instructions including either a buy or sell position and a price; at the end of the trading session, determine, based on predefined criteria, whether the trading session qualifies for a post-matching session; if the trading session qualifies for a post-matching session, providing a graphical user interface to a selected group of traders for trading in the post-matching session; and if the trading session fails to qualify for the post-matching session, terminating the trading session.