will be lower than those calculated using market value ratios, making them less
conservative estimates, not more so.
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• Since accounting returns are computed based upon book value, consistency
requires the use of book value in computing cost of capital: While it may seem
consistent to use book values for both accounting return and cost of capital
calculations, it does not make economic sense. The funds invested in these
projects can be invested elsewhere, earning market rates, and the costs should
therefore be computed at market rates and using market value weights.
Estimating Market Values
In a world where all funding was raised in financial markets and are securities
were continuously traded, the market values of debt and equity should be easy to get. In
practice, there are some financing components with no market values available, even for
large publicly traded firms, and none of the financing components are traded in private
firms.
The Market Value of Equity
The market value of equity is generally the number of shares outstanding times
the current stock price. Since it measures the cost of raising funds today, it is not good
practice to use average stock prices over time or some other normalized version of the
price.
• Multiple Classes of Shares: If there is more than one class of shares outstanding,
the market values of all of these securities should be aggregated and treated as
equity. Even if some of the classes of shares are not traded, market values have to
be estimated for non-traded shares and added to the aggregate equity value.
• Equity Options: If there other equity claims in the firm - warrants and conversion
options in other securities - these should also be valued and added on to the value
of the equity in the firm. In the last decade, the use of options as management
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To illustrate this point, assume that the market value debt ratio is 10%, while the book value debt ratio is
30%, for a firm with a cost of equity of 15% and an after-tax cost of debt of 5%. The cost of capital can be
calculated as follows –
With market value debt ratios: 15% (.9) + 5% (.1) = 14%
With book value debt ratios: 15% (.7) + 5% (.3) = 12%