Capital structure

In finance, capital structure refers to the way a corporation finances its assetsthrough some combination of equity, debt, or hybrid securities.

A firm's capital structure is the composition or 'structure' of its liabilities. For example, a firm that has $20 billion in equity and $80 billion in debt is said to be 20% equity-financed and 80% debt-financed. The firm's ratio of debt to total financing, 80% in this example, is referred to as the firm's leverage.^[1] In reality, capital structure may be highly complex and include dozens of sources of capital.

Leverage (or gearing) ratios represent the proportion of the firm's capital that is obtained through debt (either bank loans or bonds).

The Modigliani-Miller theorem, proposed by Franco Modigliani and Merton Miller, forms the basis for modern thinking on capital structure, though it is generally viewed as a purely theoretical result since it disregards many important factors in the capital structure process factors like fluctuations and uncertain situations that may occur in the course of financing a firm. The theorem states that, in a perfect market, how a firm is financed is irrelevant to its value. This result provides the base with which to examine real world reasons why capital structure is relevant, that is, a company's value is affected by the capital structure it employs. Some other reasons include bankruptcy costs, agency costs, taxes, and information asymmetry. This analysis can then be extended to look at whether there is in fact an optimal capital structure: the one which maximizes the value of the firm.

Consider a perfect capital market (no transaction or bankruptcy costs; perfect information); firms and individuals can borrow at the same interest rate; no taxes; and investment returns are not affected by financial uncertainty. Modigliani and Miller made two findings under these conditions. Their first 'proposition' was that the value of a company is independent of its capital structure. Their second 'proposition' stated that the cost of equity for a leveraged firm is equal to the cost of equity for an unleveraged firm, plus an added premium for financial risk. That is, as leverage increases, risk is shifted between different investor classes, while total firm risk is constant, and hence no extra value created.

Their analysis was extended to include the effect of taxes and risky debt. Under a classical tax system, the tax deductibility of interest makes debt financing valuable; that is, the cost of capital decreases as the proportion of debt in the capital structure increases. The optimal structure, then would be to have virtually no equity at all, i.e. a capital structure consisting of 99.99% debt.

Capital gearing ratio = (Capital Bearing Risk) : (Capital not bearing risk)

Capital bearing risk includes debentures(risk is to pay interest) and preference capital (risk to pay dividend at fixed rate).
Capital not bearing risk includes equity share capital.

Therefore, we can also say, Capital gearing ratio = (Debentures + Preference share capital) : (shareholders' funds)