Chandler recalled that the effect of leverage on a firm could be modeled by using the adjusted present-value formula, which hypothesized that debt increased the value of a firm by means of shielding cash flows from taxes. Thus, the present value of debt tax shields could be added to the value of the unlevered firm to yield the value of the levered enterprise. The marginal tax rate Chandler proposed to use was 40%, reflecting the sum of federal, state, and local taxes.