Banks and other financial institutions should allocate capital in proportion to the marginal default value of each line of business, which is the derivative of the value of the bank's default put with respect to a change in the scale of the business. Marginal default values give a unique...

We present a theory of risk capital and of how tax and other costs of risk capital should be allocated in a financial firm. Risk capital is equity investment that backs obligations to creditors and other liability holders and maintains the firm's credit quality. Credit quality is measured by the...