Government Subsidy,Investment and Financing Constraints,and the Formation of Zombie Companies

Zombie companies have serious adverse effects on economic development.The relationship between government subsidies and zombie companies is a focus in China’s supply-side structural reform.In this paper,we classify companies into two categories:investment-constrained companies lacking investment opportunities,and fi nancing-constrained companies with limited sources of capital.Based on data of A-share listed companies from 2007 to 2016,this paper examines the relationship between government subsidies and the zombification of companies subject to different types of constraints.We find that more government subsidies have been allotted to investment-constrained companies than financing-constrained ones;government subsidy is one of the various factors that have contributed to company zombification,but the correlation is only significant for investment-constrained companies;financing subsidy dedicated to expanding corporate financing is more effective in helping investment-constrained companies than government subsidies in general,but neither government subsidies nor financing subsidies are effective in preventing investment-constrained companies from turning into zombies.In the robustness test that controls the endogeneity problem of reverse causality,replaces proxy variables,lags subsidy variables and discusses the zombification of loss-making enterprises,the results are still valid.This paper provides a heterogeneous perspective to study the connection between government subsidies and the formation of zombie companies,and in view of subsidy mismatch,puts forward recommendations regarding the use of government subsidies.

Survey on Multi-period Mean-Variance Portfolio Selection Model

Due to the non-separability of the variance term,the dynamic mean-variance(MV)portfolio optimization problem is inherently difficult to solve by dynamic programming.Li and Ng(Math Finance 10(3):387-406,2000)and Zhou and Li(Appl Math Optim 42(1):19-33,2000)develop the pre-committed optimal policy for such a problem using the embedding method.Following this line of research,researchers have extensively studied the MV portfolio selection model through the inclusion of more practical investment constraints,realistic market assumptions and various financial applications.As the principle of optimality no longer holds,the pre-committed policy suffers from the time-inconsistent issue,i.e.,the optimal policy computed at the intermediate time t is not consistent with the optimal policy calculated at any time before time t.The time inconsistency of the dynamic MV model has become an important yet challenging research topic.This paper mainly focuses on the multi-period mean–variance(MMV)portfolio optimization problem,reviews the essential extensions and highlights the critical development of time-consistent policies.