We investigate covariance matrix estimation in vast-dimensional spaces of 1,500 up to 2,000 stocks using fundamental … about estimation risk in FFMs in high dimensions. We investigate whether recent linear and non-linear shrinkage methods help … to reduce the estimation risk in the asset return covariance matrix. Our findings indicate that modest improvements are …

In this article, the authors measure the impact of estimation error on latent factor model forecasts of portfolio risk … find that an estimation period of 250 days may be adequate to accurately forecast risk and factor exposures for an equally … an estimation period of 1000 days. This underscores the importance of testing risk models on optimized portfolios …