经济周期中商业信用与银行借款替代行为研究

Behavior of substitution between trade credit and bank borrowing through economic cycles: Evidence from China

对商业信用与银行借款之间的关系进行了两个扩展性研究．首先，基于公司债务的两类经典的期权理论，首次尝试导出了违约边界外生给定和内生决定两种情况下银行借款对商业信用的弹性表达式，在理论上得出替代关系和反周期的结论．其次，利用沪深两市1998—2006年上市公司的5354个样本点数据，建立了时变系数固定效应Panel模型，不仅验证了两类重要短期融资之间的替代关系在中国是成立的，更重要的是，还利用Kappa一致性检验发现了这个替代关系具有同步性的反经济周期规律，揭示了这个规律的微观企业管理战略含义是：紧缩期“雪中送炭”而扩张期应坚守商业信用政策底线．

This paper presents two further studies on the relationship between trade credit and bank borrowing. First, based on two kinds of classic option theories on corporate liability （Merton, 1974; Leland, 1994）, for the first time as far as we know, we theoretically derive two explicit formulas of elasticity of bank borrowing with respect to trade credit in the cases of default boundaries determined exogenously and endogenously respectively. Substitution between trade credit and bank borrowing and its counter-business-cycle behavior can be characterized by analysis of those elasticity formulas. Second, using a sample containing totally 5354 lines of data selected from all companies listed in Shanghai and Shenzhen stock markets of China during 1998 -2006, we estimate a time-varying coefficients panel model with fixed effects by controlling endogeneity which gives supportive evidences to the existence of substitution between trade credit and bank borrowing in China. More importantly, by Kappa consistency tests, we find the varying behavior of such substitution moves in a coinci-dently counter-business-cycle manner. This finding implies that firms in the tightening period had better choose a ＂to-send-charcoal-in-snowy-weather＂ strategy, and in the loose period, the bottom lines of trade credit policy should be strictly stuck to.