A semi-parametric factor-GARCH model for high dimensional covariance matrix estimation
摘要
In this paper, we establish a semi-parametric factor-GARCH (Generalized Autoregressive Conditional Heteroskedasticity) model to estimate covariance matrix within a high-dimensional framework where both factors and factor loadings are unobservable and the data shows heteroskedasticity. The basic idea is to use projection technique to remove noise components, leading to a more precise estimation of the covariance matrix. We demonstrate that our model is robust when the sample size is finite and is particularly effective in high-dimensionality, low-sample-size settings. Asymptotic theories are developed for the proposed estimation. A simulation study is conducted to evaluate the performance of the proposed model, and a real example is provided to illustrate this approach.