Agricultural producers typically are faced with risk about the yields they will experience and the prices they will receive. Stabilisation schemes can spread risk and thereby reduce the risk faced by individual producers. The risk-reducing capacity of a scheme and the cost of risk reduction depend upon the design of the scheme. In particular, it is important to distinguish between risk and instability. A classification of scheme designs is presented to bring out the effects of various design types. Schemes for the wheat industry are given most attention.