The QPLU$ Merino breeding project began in the early 1990s. The aim of the project was to demonstrate the efficiency of using a selection index to achieve breeding objectives. A number of selection lines were created from three strains of Merino sheep. During the ten-year course of the project, selection of each line was undertaken using an index based on measurements of fleece weight and fibre diameter. Different emphases were placed on each trait in each selected line. This paper estimates the potential aggregate returns of the project to the Australian sheep and wool industries using an equilibrium displacement model.