a method for performing financial trading amongst a plurality of alternative trading systems using a common financial computer platform . the method including the steps of receiving at the common financial computer platform a buy - order for a prescribed number shares at a prescribed price . electronic communication is then established between the common financial computer platform and each of the plurality of alternative trading systems . at least a portion of the buy - order is then submitted from the common financial computer platform to each of the plurality of alternative trading systems . the common financial common platform then monitors each of the plurality of alternative trading systems to determine if at least a portion of the buy - order was executed by one of the plurality of alternative trading systems . and if yes , then that indicated execution for one of the plurality of alternative trading systems is automatically accepted and automatically canceled are the remaining buy orders that were submitted to the other alternative trading system which were not yet executed .