However, when there is growth, the value of the tax shield is not equal to TD as it was in the MM model. If the firm uses debt and g is positive, then, as the firm grows, the amount of debt will increase over time, hence the size of the annual tax shield will also increase at the rate g, provided the debt ratio remains constant. Moreover, the value of this growing tax shield is greater than the value of the constant tax shield in the MM analysis.