中文摘要：

基于世界银行调查数据,采用Heckman样本选择模型研究了内部融资、银行信贷和商业信用这三种融资方式对企业投资效率的影响。研究发现,内部融资和银行信贷会降低企业的投资效率,而商业信用可以提升企业的投资效率。从融资约束的角度来看,商业信用对融资约束强和融资约束弱的企业的投资效率都有显著的促进作用。内部融资和银行信贷对企业投资效率的负面影响会相互强化,商业信用则能够减弱内部融资和银行信贷对企业投资效率的抑制作用。

英文摘要：

Based on the survey data from the World Bank, this paper studied how the three financing modes——internal financing, bank credit loan and trade credit——affect enterprise investment efficiency by Heckman sample selection model. The result shows that internal financing and bank credit loan have a negative effect on enterprises investment efficiency while trade credit has a positive effect. From the perspective of financing constraints, trade credit can improve the investment efficiency of both enterprises facing strong financing constraints and those facing weak financing constraints. The negative effects of internal financing and bank credit loan can be enhanced each other, but trade credit can restrain the negative effects.