An exact penalty method for group-sparse portfolio selection
摘要
The current portfolio optimization problem consistently exhibits a group-sparse structure due to similarities within an industry. In this paper, we consider a group-sparse portfolio selection (GSPSO) problem. By decomposing the difference of two convex functions, we formulate an exact penalty method for GSPSO, where the group-sparsity constraint is enforced via a regularizer. In particular, we provide an explicit estimate for the penalty parameter in the long-only case. Consequently, we develop an efficient algorithm based on proximal difference-of-convex (DC) methodology. We prove that the proximal DC method converges to an