System and method of allocating an incoming order to standing orders

A method of allocating a quantity of an incoming order for a product develops a value that indicates a portion of the incoming order this is to be allocated using a FIFO algorithm and allocates a first portion of the incoming order to standing orders using the FIFO algorithm. The method further allocates a second portion of the incoming order to standing orders using a pro-rata algorithm, wherein the step of allocating the second portion leaves a remaining quantity of the incoming order. In addition, the method allocates the remaining portion to the standing orders using a FIFO algorithm.