The dollar cost for removing each kg of P was determined by SNC based on its history of delivering projects. Using earlier trading formulae (Batchelor, 1999; Draper, 1997), it was possible to calculate the amount of P controlled for a number of projects completed by SNC prior to the trading programme starting. Since the total cost for each of these projects was known, it was possible to derive an average cost of CAD 400 (2009 figures) for each kg of P. This figure is reviewed by South Nation Conservation annually, and is generally increased by yearly inflation figures.