The cost of conserving on-site biodiversity at a residential development project on the urban fringe, for example, may be very high when compared to the costs of conserving equivalent biodiversity at an offset site located on agricultural land further afield. The flexibility to purchase offsets from off-site suppliers enables developers to seek approval for a more cost-effective combination of on-site biodiversity conservation and permissible offset purchases. In doing so, an offset scheme can simultaneously create economic value from transactions and lower the costs of meeting a given conservation objective.