Since Almeida et al. (J Financ 59:1777–1804, 2004), there has been a long debate on whether the cash flow sensitivity of cash (CFSC) measures financial constraints. Like all measures of financial constraints, CFSC is not a perfect one. Thus, how to measure financial constraints with CFSC effectively is an important issue. This paper shows that when a firm does not save through external financing, the CFSC can be effectively used to measure financial constraints. However, for firms saving from external financing, CFSC does not effectively measure financial constraints, especially when firms use external funds as substitutes for internal ones. The reason is that CFSC does not only reveal the propensity to save from cash flows but also the internal-external financing relation, which is not necessarily linked to financial constraints. Two identification methods are used to confirm our findings.

由于阿尔梅达等人。(J Financ 59:1777–1804, 2004)，关于现金的现金流敏感性 (CFSC) 是否衡量财务约束存在长期争论。与所有财务约束措施一样，CFSC 并不是一个完美的措施。因此，如何有效衡量CFSC的财务约束是一个重要问题。本文表明，当企业不通过外部融资进行储蓄时，CFSC 可以有效地用来衡量财务约束。然而，对于通过外部融资储蓄的企业，CFSC并不能有效衡量财务约束，特别是当企业使用外部资金替代内部资金时。原因在于，CFSC不仅揭示了现金流的储蓄倾向，还揭示了内部与外部融资关系，而这与财务约束没有必然联系。使用两种识别方法来证实我们的发现。