Several studies of Modigliani and Miller (MM) (1958) examined the reasons for
economists' focussed attention on the appropriate choice of debt and equity.
Consequently, numerous theories emerged based on agency costs, asymmetric information, product/input
market interactions, corporate control consideration, and taxes. These
theories, while validating the central message of MM that optimality of capital structure is an issue inextricably linked
to taxes or some specifically identified market imperfections, however,
failed to provide a definitive answer to optimal capital structure choice (that would maximize firm value) in the presence
of market imperfections.
Barclay and Smith (1999) suggest that most competing theories of optimal capital
structure are not mutually exclusive.
Consequently, it may not be possible to reject any theory in favor
of another, as there exists a possibility of more than one of them being right at the same time.
Also noteworthy is the fact that many of the variables that affect capital structure choice are
often difficult to measure; for example, the variable `growth' has been represented in empirical
studies through growth of assets, growth in sales,
market-to-book ratio or growth in capital
employed. Which of them is the closest proxy for growth is a debatable
issue, and selecting one among them as an independent variable in a regression model in terms of
goodness-of-fit criteria might result in biasing the interpretation of the significance levels of the tests. |