库存理论与期货价格:基于沪铜合约的实证检验

库存理论是期货价格的重要解释依据之一。文章以中国上海期货交易所的阴极铜合约作为研究对象,通过建立利息调整基差(iab)与库存量之间的内在函数关系,对库存理论的主要含义进行了实证检验。结果基本上不支持库存理论的基本含义,甚至波动性的非对称特征都没有得到证实。由于受数据可得性的限制,所采用的数据单一、样本期短,这使作者无法排除数据缺陷影响研究结果的可能性。     

Pensions with endogenous and stochastic fertility

This paper studies the design of a pay-as-you-go social security system in an overlapping generations model where fertility is in part stochastic and in part determined through capital investment. If investments are publicly observable, pension benefits must be linked positively to the level of investment, and payroll taxes negatively to the number of children. The outcome is characterized by full insurance with all parents, regardless of their number of children, enjoying identical consumption levels. Without observability, benefits must increase, and payroll taxes decrease, with the number of children. The second-best level of investment, and the resulting average fertility rate, are less than their corresponding first-best levels.