An agreement between a host government and a contractor under which the host pays the contractor an agreed price for all volumes of hydrocarbons produced by the contractor. Pricing mechanisms typically provide the contractor with an opportunity to recover investment at an agreed level of profit. These agreements may include financial incentives for more efficient, lower cost developments and production levels higher than the minimum level agreed. These agreements may give rights to oil volumes and generally carry a risk for the contractor. They may allow booking of reserves.