The paper uses a signalling equilibrium to explain the market's reaction to the announcement of a firm's financing decision. In our model, a firm can issue one of the following securities: convertible debt with a different conversion ratio, straight debt, and stock. We identify conditions under which the conversion ratio of a convertible debt issue serves as a credible signal of a firm's private information, given the continuous distribution of attributes (information) across firms. In this signalling equilibrium, we find that the lower the expected future earnings, the higher the conversion ratio of a convertible debt issue. At the limit, firms that expect the highest earnings will use straight debt financing, and firms that expect the lowest earnings will use equity financing. Based on the signalling equilibrium, we predict that at announcement of a convertible debt issue, negative abnormal common stock return increases in absolute value with the conversion ratio.

This paper develops a signalling model of call of convertible securities (bonds or preferred stock) in the presence of corporate taxes and asymmetric information about future earnings. In equilibrium, managers with relatively unfavorable information call to force convertible holders to convert to common stock (in spite of the loss of corporate tax benefits if the convertibles are bonds), while those with relatively favorable information do not call. The model predicts that the announcement period common stock returns are more negative at the call of convertible bond than at the call of convertible preferred stock. Furthermore, we predict that when the importance of the tax deductibility of interest differs among firms, so does the stock price reaction to the announcement of convertible debt call. Specifically, the loss of equity value at the announcement decreases with the amount of non-debt tax shield that the calling firm owns, decreases with the book value of convertible debt called, and increases with corporate taxes.