The least absolute deviation (LAD) regression is a useful method for robust regression, and the least absolute shrinkage and selection operator (lasso) is a popular choice for shrinkage estimation and variable selection. In this article we combine these two classical ideas together to produce...

We propose a novel varying coefficient model, called principal varying coefficient model (PVCM), by characterizing the varying coefficients through linear combinations of a few principal functions. Compared with the conventional varying coefficient model (VCM; Chen and Tsay, 1993; Hastie and...

In Chinese stock market, firms reporting two consecutive annual losses are subject to special treatment (ST), with further losses causing the firms' stocks to be suspended from trading or to be delisted. We argue that these earnings-based delisting requirements are misconstrued. Such policies...