Consequences of discretion in the formation of commodities policy
构建一个内生的大宗商品价格支持政策模型，分析私人库存与投机行为如何影响政策效果，解释市场中的泡沫和异常波动，并指出缺乏承诺能力的政府可能无力或被迫实施价格支持。
In a simple model of endogenous primary-commodity price-support policy, (i) policy is affected by private inventories, and (ii) private inventories are affected by speculative attempts to forecast policy. The interaction between these two forces is rich, yielding bubbles and extrinsic volatility, thus helping to explain some odd episodes observed in commodity markets. In addition, under some conditions a government that wishes to support the price but is unable to commit to future action may be impotent; and a government that does not want to support the price may be “trapped” into doing so by speculative activity.