To know when to release stocks, a public agency sets a trigger price. When the price reaches the trigger, stocks are released to fill the demand so that prices will not rise higher. The ceiling price is the price above which prices will not be permitted to rise, which protects consumers. To be viable, the margin between the buying and selling prices must cover the direct costs of stabilization. Price stability can also be achieved by varying imports and exports.
Distribution becomes crucial to maintaining stability.
Imports must be distributed in all regions or prices will rise in the regions where supplies are short. If trade transaction costs, including delivery, are high, stockholding may be cheaper than importing. A system of taxes and subsidies on imports and exports can be used to shelter domestic prices from variations in world prices. When the world price rises, an exporting country can impose a marginal tax on exports to prevent the domestic price from rising proportionally. An importing country taxes imports when world prices are low and subsidizes them when world prices rise.