摘要：For the ten crop seasons 1979-80 to 1988-89, returns to producers in the Australian wheat industry were underwritten by a government-guaranteed price floor. Similar schemes operate in other rural industries (dairy, apples and pears, dried fruits). Although the underwriting provisions have only been triggered once (in the 1986-87 season), the provision of this scheme has acted to reduce the risk normally associated with returns to producers of wheat in all years of its operation. This reduction in risk has been granted free-of-charge by the Commonwealth Government. The guaranteed price can be viewed as a put option taken out by the Government on behalf of growers - it gives growers the option to sell to the Australian Wheat Board at this floor price. The aim of this paper is to apply to this underwriting arrangement the Black-Scholes formula for valuing options, in order to estimate the cost that growers would otherwise have had to pay to obtain cover (through put options) equivalent to the guaranteed price. We also estimate the magnitude of this form of assistance to the industry, which (until now) has not been taken into account unless the returns to growers fell below the guaranteed price.
