1. A computer readable medium comprising instructions that, when executed, cause a computing device to at least: receive a definition for a spread, wherein the spread is between a first tradeable object and a second tradeable object, the definition determining whether the first tradeable object is to be bought or sold and whether the second tradeable object is to be bought or sold to complete the spread; receive a first market data from an electronic exchange, the first market data comprising a highest bid price and a lowest ask price currently available for the first tradeable object and a last traded price for the first tradeable object; receive a second market data from an electronic exchange, the second market data comprising a highest bid price and a lowest ask price currently available for the second tradeable object and a last traded price for the second tradeable object; detect a change in the first market data; electronically estimate the spread value responsive to the change in the first market data using the definition for the spread; wherein the spread value is based on a highest bid price for the second tradeable object when the second tradeable object is to be sold or the spread value is based on a lowest offer price for the second tradeable object when the second tradeable object is to be bought; and display the spread value on a screen of an electronic terminal in relation to an axis of price levels.