Capital Structure Theory 491
3 .While theory and empirical work support the general shape of the curve in Fig-
ure 13-3, this graph must be taken as an approximation, not as a precisely defined
function.
Signaling Theory
MM assumed that investors have the same information about a firm’s prospects as its
managers—this is called symmetric information.However, in fact managers often
have better information than outside investors. This is called asymmetric informa-
tion,and it has an important effect on the optimal capital structure. To see why, con-
sider two situations, one in which the company’s managers know that its prospects are
extremely positive (Firm P) and one in which the managers know that the future looks
negative (Firm N).
Suppose, for example, that Firm P’s R&D labs have just discovered a non-
patentable cure for the common cold .They want to keep the new product a secret as
long as possible to delay competitors’ entry into the market .New plants must be built
to make the new product, so capital must be raised .How should Firm P’s management
raise the needed capital? If it sells stock, then, when profits from the new product start
flowing in, the price of the stock would rise sharply, and the purchasers of the new
stock would make a bonanza .The current stockholders (including the managers)
would also do well, but not as well as they would have done if the company had not
sold stock before the price increased, because then they would not have had to share
the benefits of the new product with the new stockholders.Therefore, one would expect
a firm with very positive prospects to try to avoid selling stock and, rather, to raise any required
new capital by other means, including using debt beyond the normal target capital structure.^12
FIGURE 13-3 Effect of Leverage on Value
Value
Value Added by
Debt Tax Shelter
Benefits
MM Result Incorporating the
Effects of Corporate Taxation:
Value if There Were No
Bankruptcy-Related Costs
Value Reduced by
Bankruptcy-Related Costs
Actual Value
Value if the Firm
Used No Financial
Leverage
0DD 12 Leverage
Value with
Zero Debt = $20
Threshold Debt Level
Where Bankruptcy
Costs Become Material
Optimal Capital Structure:
Marginal Tax Shelter Benefits =
Marginal Bankruptcy-Related Costs
(^12) It would be illegal for Firm P’s managers to personally purchase more shares on the basis of their inside
knowledge of the new product. They could be sent to jail if they did.