ASYMMETRIC INFORMATION AND THE LACK OF PORTFOLIO DIVERSIFICATION*
构建理论模型，证明信息不对称导致投资者偏好本地股票，从而持有分散不足的投资组合。模型假设本地投资者在识别本地投资机会的排序上优于外地投资者，且卖空成本高。
There is pervasive evidence that individuals invest primarily in local stocks and thus hold poorly diversified portfolios. The present article develops a theoretical model in which the presence of informational asymmetries introduces home equity bias. The main departure from previous theoretical work is the assumption that local investors outperform nonlocal investors in identifying the correct ranking of local investment opportunities, instead of possessing superior information about the aggregate performance of the local stock market. The second key assumption is based on the evidence that short‐selling is a costly activity.