In the previous sections we discussed the nature of agency costs associated with outside
claims on the firm—both debt and equity. Our purpose here is to integrate these concepts into the
beginnings of a theory of the corporate ownership structure. We use the term “ownership
structure” rather than “capital structure” to highlight the fact that the crucial variables to be
determined are not just the relative amounts of debt and equity but also the fraction of the equity
held by the manager. Thus, for a given size firm we want a theory to determine three variables:59
Si : inside equity (held by the manager),
So : outside equity (held by anyone outside of the firm),
B : debt (held by anyone outside of the firm).
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