An electronic trading system is described herein. More specifically, the electronic trading system may relate to the substantially simultaneous trading of cash instruments and their related futures contracts for interest-rate related instruments. The electronic trading system may also be used to allow a user (such as a market maker or other suitable participant) to gauge his chance of success at completing both sides of a basis trade within a preferably pre-determined or pre-set interval, while knowing in advance the specific weighting algorithm that will be applied to the basis trade. The electronic trading system may also be used to allow a user to predetermine the exact weighting algorithm to be used on such a basis trade, and to adjust those preferences where necessary or desired.