'q,' Corporate Investment, and Balance Sheet Behavior
分析企业实际投资与金融决策的相互关联，指出资本成本受融资方式影响，并探讨杠杆如何影响投资决策，对研究企业财务与投资关系的学者有参考价值。
A GOAL OF RESEARCH on the business sector of the flow-offunds model is to analyze real and financial investment decisions of firms. In theory, and in reality, these decisions should be, and are, linked within a simultaneous framework. The cost of capital to a firm is not determined wholly exogenously but depends on its means of financing, and the timing of a firm's capital outlays is contingent upon the availability of funds. Economists have traditionally approached the theory of investment by hypothesizing that decisions first are made about expenditures for physical capital, and then decisions are made about their financing. Such sequential separation of real and financial capital decisions was most elegantly justified in a series of articles by Modigliani and Miller [5]. However, as Stiglitz [7] and others have shown, the proposition depends not only on the existence of perfect capital markets but also on other conditions such as the absence of taxes, equality of borrowing and lending rates, independence of expectations of real returns and firms' financial policies, and the absence of the possibility of bankruptcy (see Scott [6]). In a previous article [2] we presented a two-period model of the firm in which the debt-equity ratio was determined within a framework where firms consider trade-offs of cost and tax advantages of additional debt against real costs of potential bankruptcy. We also indicated, to some extent, how leverage could be expected to influence the firm's real investment decisions. It was shown that the optimum amount of debt in the firm's capital structure depends upon the corporate tax rate, bor-