1. An apparatus, comprising: a processor; and a memory, in which the memory stores software instructions that, when executed by the processor, cause the processor to: receive, from a trader, a trading order for a particular quantity of a trading product, in which a first portion of the particular quantity is a displayed quantity, and a second portion of the particular quantity is a reserved quantity; identify a decay rule stored in the trading order; disclose the displayed quantity of the trading order to one or more market centers; receive a counterorder for another particular quantity of the trading product; determine that the counterorder matches the trading order; fill the displayed quantity of the trading order with at least a portion of the another particular quantity of the counterorder; determine that the reserved quantity of the trading order is greater than zero; replenish the displayed quantity of the trading order with a portion of the reserved quantity of the trading order, in which a remaining portion of the reserved quantity is left over after replenishing the displayed quantity; determine that the remaining portion of the reserved quantity of the trading order is greater than zero; and reduce the remaining portion of the reserved quantity in accordance with the decay rule.