Nonfundamental Speculation Revisited
指出Madrigal(1996)模型中线性纯策略均衡可能不存在，因其遗漏了二阶条件；当非基本面投机者对噪声交易的信息足够精确时，均衡不存在。在均衡存在的参数区域，还发现了原论文的计算错误。
ABSTRACT We show that a linear pure strategy equilibrium may not exist in the model of Madrigal (1996), contrary to the claim of the original paper. This is because Madrigal's characterization of a pure strategy equilibrium omits a second‐order condition. If the nonfundamental speculator's information about noise trading is sufficiently precise, a linear pure strategy equilibrium fails to exist. In parameter regions where a pure strategy equilibrium does exist, we identify a few calculation errors in Madrigal (1996) that result in misleading implications.