Published in Wilmott Magazine, Mar/Apr 2008, pp. 62-68
Visitor number 17448 as of April 25, 2007
Incorporating Default Risk into
Hamada's Equation for Application to Capital Structure
Ruben
D. Cohen (e-mail)
Implemented widely in the
area of corporate finance, Hamada’s Equation enables one to separate the
financial risk of a levered firm from its business risk. The relationship, which results from
combining the Modigliani-Miller capital structuring theorems with the Capital
Asset Pricing Model, is used extensively in practice, as well as in academia,
to help determine the levered beta and, through it, the optimal capital structure of
corporate firms.
Despite its regular use in the industry, it is acknowledged that the
equation does not incorporate the impact of default risk and, thus, credit
spread - an inherent component within every levered institution. Several attempts have been made so far to
correct this, but, for one reason or another, they all seem to have their
faults. This, of course, presents a
major setback, as there is a strong need, especially by practitioners, to
have in place a solid methodology to enable them to assess a firm’s capital
structure in a consistent manner. This
work addresses the issue and provides a robust modification to Hamada’s
Equation, which achieves this consistency.